Spring Training is underway for all 30 MLB clubs, but as exciting as it is to see the return of Major League stars, it's also a time to dream about the next wave of baseball talent. With the help of MLB.com's beat writers, here's a prospect to keep an eye on for each and every team in 2019.

AMERICAN LEAGUE EAST

Blue Jays: Vladimir Guerrero Jr., 3B
The Blue Jays might be in the process of rebuilding, but their Spring Training is must-see TV because of one player. Guerrero, arguably one of the most hyped prospects in history, is in big league camp for the first time in his career. Guerrero appeared in a handful of spring games for Toronto in 2018, but he's never been a full participant in camp, and this is first time fans get to watch his progress from start to finish. When Vlad Jr. is up, the entire baseball world is watching. If Guerrero comes anywhere close to matching the hype, this will be a season to watch, and the son of a Hall of Famer already is making a name himself with some of his exploits at the plate. -- Gregor Chisholm

Orioles: Yusniel Diaz, OF
Orioles camp is full of blue-chippers eager to show the new regime what they can do as the club heads into a season in which big league opportunities figure to be available in plenty. The crop includes fast-rising Ryan Mountcastle, rebound candidates Hunter Harvey and Austin Hays, and late bloomers Ryan McKenna and Dean Kremer. But the obvious choice here is Yusniel Diaz, the prize of the Manny Machado trade and the Orioles' No. 1 prospect per MLB Pipeline. The 22-year-old Cuban slumped at Double-A last summer, but has generally rose steadily since signing with the Dodgers in November 2015. He is considered a potential five-tool player with an advanced approach at the plate, an ability to play all three outfield positions and a shot at debuting in Baltimore as early as this summer. -- Joe Trezza

Rays: Nate Lowe, 1B
Once the Rays decided to trade Jake Bauers to the Indians this offseason, it became clear that the organization believes Nate Lowe is the first baseman of the future. Lowe won the Rays' Minor League Player of the Year Award in 2018 after dominating three levels in the Minors. The Rays' No. 8 prospect according to MLB Pipeline finished with 27 homers in 2018, and scouts have little doubt that the power will translate to the Majors due to his 6-foot-4, 235-pound frame. Lowe is one of the 24 non-roster invitees at this year's Spring Training, and it will be interesting to see what Lowe can show in just over a month. There's a good chance we see Lowe at the big league level at some point in 2019, and the 23-year-old already has displayed his power this spring. -- Juan Toribio

Red Sox: Bobby Dalbec, 3B
The power-hitting third baseman is in big league camp for the first time, taking aim at the replica Green Monster at JetBlue Park. Dalbec has the best raw power in Boston's farm system, and his batting practice sessions are a must-see event for fans roaming the back fields. But Dalbec isn't just about offense; he was a much-improved defender at the hot corner last season, displaying a quick first step and a strong arm. Look for Dalbec to start 2019 at Double-A and likely finish it at Triple-A. A September callup isn't out of the question. -- Ian Browne

Yankees: Estevan Florial OF
A left-handed hitting center fielder with power, speed and arm strength, Florial’s raw athleticism continues to excite the Yankees' decision-makers. The 21-year-old lost two months of development time last season due to right hamate surgery, but appears to have bounced back strong this spring. General manager Brian Cashman recently said that Florial "looks the part and plays the part" of a prospect that the organization can dream on. Florial is likely to begin the season with Class A Advanced Tampa, but he could see Double-A Trenton before long, with an estimated big league arrival of 2021. -- Bryan Hoch

AMERICAN LEAGUE CENTRAL

Indians: Bobby Bradley, 1B
For those who enjoy the long ball, Bradley is one to keep an eye this spring. The 22-year-old first baseman has demonstrated plus power in every step of his Minor League career, launching at least 20 home runs over the last four years (27 in Class A Advanced Lake County in 2015, 29 for Class A Advanced Lynchburg in '16, 23 at Double-A Akron in '17 and 27 between Double- and Triple-A in '18). In '16, he also knocked in an impressive 102 runs in 131 contests. Bradley's powerful bat is definitely something the Indians could use in their lineup once he continues to improve his defense and trim his strikeout rate. But it may not be too much longer until he gets his chance to hit long balls and drive in runs for the big league club. -- Mandy Bell

Royals: Richard Lovelady, LHP
As we've mentioned numerous times on royals.com, Lovelady, 23, doesn't have to go on the 40-man roster until next fall. But Lovelady, who posted a 2.47 ERA last year at Triple-A Omaha with nine saves, may force the Royals' hand this spring. And there certainly are plenty of open spots in the bullpen for Lovelady to grab, so a lot of eyes are on him as the spring progresses. He has swing-and-miss stuff and a bulldog mentality, and general manager Dayton Moore brought his name up at the team's FanFest as one of those pitchers who could be the next Greg Holland, Kelvin Herrera or Wade Davis. Lovelady just needs an opportunity. -- Jeffrey Flanagan

Tigers: Casey Mize, RHP
Mize isn't pushing for a roster spot after just 13 Minor League innings last summer. But what last year's top Draft pick shows in camp should play a big role in determining his eventual path to the big leagues.

"I'm not going to even touch the delivery," pitching coach Rick Anderson said of Mize at TigerFest this offseason. "You just let him get adapted to where he's at. I'm excited to see him, just as I was when [Beau] Burrows and [Matt] Manning came up. You get a chance to see these guys and then you sit down with [roving pitching instructor] A.J. Sager and the Minor League people and talk about where we're going with them and what their thoughts are. It's going to be fun to see him."

The Tigers' decision to invite Mize to Major League camp is similar to what Detroit did with fellow right-hander Alex Faedo, their previous year's top Draft pick. The Tigers rested Faedo for the summer of 2017 after taking him with their first pick, letting him rest his arm following extended work during the University of Florida's run to the College World Series. Before Faedo embarked on his first pro season, the Tigers gave him a glimpse of Major League pitchers and the routine they build to prepare for a season. He pitched in the Tigers' spring exhibition game against Florida Southern College before heading over to Minor League camp. Expect much of the same for Mize. -- Jason Beck

Twins: Alex Kirilloff, OF
Kirilloff missed the entire 2017 season after undergoing Tommy John surgery, and his only goal entering '18 was to play a full season of healthy baseball. The former first-round selection from the '16 MLB Draft not only stayed healthy, but also had one of the most productive seasons in the Minor Leagues, leading all full-season Minor League hitters in doubles (44) while hitting .348/.392/.578 with 20 homers and 101 RBIs across two levels. The 21-year-old was named the Twins' Minor League Player of the Year, shot up to No. 9 on MLB Pipeline's top 100 prospects list and earned an invite to big league camp.

"I'd never had an injury like that, that caused me to miss that much time," Kirilloff said. "But once it got past that point and I accepted everything, I took it as a challenge and tried to make myself better from it." -- Do-Hyoung Park

White Sox: Eloy Jiménez, OF
White Sox fans believe they have a star in the making in Jimenez. Those same fans were disappointed to not have Jimenez come to the Majors at all in 2018, especially after getting a glimpse of his raw power during Spring Training and then watching Jimenez tear through the Minors offensively. The game's No. 3 prospect overall, per MLB Pipeline, worked diligently on his conditioning in the offseason and seems primed for an impressive rookie campaign, which should begin sometime in mid-April. -- Scott Merkin

AMERICAN LEAGUE WEST

Angels: Jo Adell, OF
Adell, ranked as the No. 14 overall prospect by MLB Pipeline, is a true five-tool center fielder who has continued to make impressive adjustments in the Minors. He's coming off a breakout year that saw him hit a combined .290/.355/.543 with 20 homers, 32 doubles and 15 stolen bases in 99 games across three levels, including his first stint at Double-A despite being only 19. He was in Major League camp for the first time this spring, but isn't likely to reach the Majors in 2020. Likely ticketed to open the year at Double-A, Adell is expected to remain in Arizona to rehab a Grade 2+ right ankle sprain and a Grade 1+ left hamstring strain sustained in a Cactus League game. Despite the injury, Adell is the club's most exciting home-grown prospect since Mike Trout. -- Rhett Bollinger

Astros: Forrest Whitley, RHP
Whitley, the seventh-ranked overall prospect by MLB Pipeline, is one of the Astros' most highly touted prospects in the last couple of years. Whitley, who dominated at the Arizona Fall League after being held to 26 1/3 innings at Double-A Corpus Christi last year following a 50-game suspension and a pair of injuries, will probably begin the season at Triple-A Round Rock and should make his way to Houston at some point in 2019. There's a reason the Astros came out publicly and said the 6-foot-7 Whitley isn't available in trades this offseason. -- Brian McTaggart

Athletics: Jesus Luzardo, LHP
The A's top prospect, all of 21 years old, is the most intriguing Opening Day rotation candidate. The southpaw sensation -- who was recently anointed the game's top left-handed pitching prospect by MLB Pipeline -- climbed three levels in the Minors in 2018 and put together a 10-5 record and 2.88 ERA with 129 strikeouts in 109 1/3 innings. Despite having just four games under his belt at the Triple-A level, the A's won't hesitate to throw him in the big league rotation with a strong spring showing. Conversely, they don't want to rush him if they feel he's not ready, and wouldn't shy away from giving him more time at Triple-A. Either way, the hype is real. Luzardo is armed with a premium arsenal -- including a high-90s fastball that features a high spin rate and an elite changeup -- and the kind of pinpoint command that typically eludes young pitchers. -- Jane Lee

Mariners: Kyle Lewis, OF
With all the offseason moves by Jerry Dipoto, the Mariners are suddenly loaded with interesting young prospects, including promising pitchers Justus Sheffield, Justin Dunn and Erik Swanson, who all could impact the rotation before long. Nine of the club's Top 30 prospects per MLB Pipeline were acquired this winter. But there's a returning prospect who is even more intriguing to keep an eye on, as Lewis -- the club's No. 1 Draft pick in 2016 -- finally looks to be at full strength in his return from knee surgery. In his first Major League camp, the 23-year-old is re-establishing himself as a key part of the franchise's future plans. -- Greg Johns

Rangers: Taylor Hearn, LHP
Spring Training is giving the Rangers a chance to take a good look at Hearn, 24, who was acquired from the Pirates in a trade for Keone Kela at the end of July. He is at the forefront of a group of Minor League starting pitchers who are expected to make an impact at the big league level in two to three years. Hearn, who is from nearby Royse City, has a fastball that hits 97-98 miles per hour but still has to refine his location. He has a good feel for a changeup, but is still working on his slider. He could end up with a future in the bullpen, but the Rangers will give him a chance to start. -- T.R. Sullivan

NATIONAL LEAGUE EAST

Braves: Cristian Pache, OF
Andruw Jones says Pache is already the best defensive outfielder within an organization that includes Ender Inciarte, who has won three straight Gold Glove Awards. Other evaluators have opined the 20-year-old prospect might be the game's best defensive outfield prospect. The young outfielder hit the first nine homers of his professional career last year and his power will likely increase as he continues to physically mature. Pache held his own while experiencing his first big league Spring Training last year. His presence during this year's camp should give Braves fans further reason to be excited about the possibility he might be roaming the outfield with Ronald Acuña Jr. at some point during the 2020 season. -- Mark Bowman

Marlins: Monte Harrison, OF
Entering his second full season in the Marlins organization, Monte Harrison is in more of a comfort zone. Harrison was part of the Christian Yelich trade with the Brewers after the 2017 season. A five-tool-caliber player, the 23-year-old has impressed in Spring Training with his work ethic and willingness to make adjustments at the plate. Reducing his strikeout rates and making more consistent contact, obviously, are his biggest issues after he struck out 215 times in 2018 at Double-A Jacksonville. In all probability, Harrison could use a full season of more development at Triple-A New Orleans to be completely big league ready. But his time may come at some point in 2019, depending on how he is performing.

"Monte has come a long way," manager Don Mattingly said. "If you really look at camp last year, his swing had so much movement. To now, he's made huge strides. He continues to work on that. He's another guy who has worked really hard. Monte is focused on what he's doing. He has come a long way. If he makes another jump like that, to next spring or through this season, you may be looking at a guy who's going to be really dangerous." -- Joe Frisaro

Mets: Pete Alonso, 1B
A vocal segment of Mets fans wanted top-ranked prospect Pete Alonso in the Majors last season. They're back in full-throated support of Alonso this spring, as he attempts to make the Mets' Opening Day roster despite odds stacked against him. While Alonso has nothing left to prove offensively in the Minors, slugging 36 home runs over two levels last season, the Mets must keep him down until mid-April if they want to ensure an extra year of team control.

Regardless of that decision, Alonso is under a microscope this spring, as the Mets try to figure out if he really is their first baseman of the future -- particularly on defense, where he has struggled since the Mets drafted him in the second round in 2016. If all goes well, Alonso has potential to develop into one of the best right-handed sluggers in baseball. -- Anthony DiComo

Nationals: Victor Robles, OF
Robles, the club's top prospect and MLB Pipeline's No. 4 overall prospect in baseball, is a big reason why the Nationals could be OK after losing Bryce Harper. Had he not hyperextended his left elbow on a diving catch last April, Robles would have received his chance in D.C. last season. Instead, his friend Juan Soto got the chance and ran with the opportunity. This year will be Robles' turn.

Washington is going to hand Robles the job as the everyday center fielder because the team believes he is ready to show off all of his tools. Those include speed around the bases and in the outfield, instincts and a strong arm on defense, and an approach at the plate that they do not believe will be overwhelmed by big league pitching, along with enough power to make pitchers pay for mistakes. Robles is about to get his chance to prove himself this season, and the Nationals hope he will end up roaming the outfield at Nationals Park for years to come. -- Jamal Collier

Phillies: Adam Haseley, OF
The Phillies selected Haseley with the eighth overall pick in the 2017 MLB Draft, and there is some thought that he could push for a job on the big league roster later this season, if he plays well and if there is a need. Haseley opened last season with Class A Clearwater before being promoted to Double-A Reading. He put up impressive numbers with Reading, batting .316 with six home runs, 17 RBIs and an .880 OPS in 159 plate appearances. The Phillies' signing of Bryce Harper obviously hurts Haseley's chances to make a big league impact in 2019, but on the other hand, outfielders like Odúbel Herrera and Aaron Altherr are trying to rebound from disappointing seasons, and Roman Quinn has an extensive injury history. So there is a chance an opportunity still could present itself at some point this year. -- Todd Zolecki

NATIONAL LEAGUE CENTRAL

Brewers: Keston Hiura, 2B
In this case, the must-see prospect in camp might also be the one with the chance to make the biggest impact. Hiura impressed manager Craig Counsell and the Major League staff last year by batting .419 with a .986 OPS in 31 Cactus League at-bats before a solid season split between Class A Advanced Carolina and Double-A Biloxi -- as well as a strong showing in the Arizona Fall League, where he posted a .934 OPS. President of baseball operations David Stearns has already said Hiura will begin the season in the Minors, but even with Mike Moustakas re-signed and ticketed for second base, Hiura could have callup potential once Super 2 territory is cleared. -- Adam McCalvy

Cardinals: Alex Reyes, RHP
Reyes has been the Cardinals' top-ranked prospect for four straight seasons, but he's eager to graduate from that list. He missed 2017 while recovering from Tommy John surgery and made just one start (four innings) in 2018 before requiring surgery to repair a torn tendon in his lat muscle. His rehab schedule has him on track to be ready to pitch in Grapefruit League games this week, and the Cards will use the rest of the spring to assess his health and optimal fit for the season ahead. They remain open to using him as a starter or reliever, depending on need. -- Jenifer Langosch

Cubs: Nico Hoerner, SS
Chicago built its core through position players at the top of the MLB Draft, and the club is hoping that Hoerner (taken 24th overall in the '18 Draft) will soon fit into that same category. The 21-year-old Stanford product has certainly turned heads since turning pro. A left elbow issue limited Hoerner to 14 games last season, but the shortstop posted a 1.021 OPS in 60 plate appearances. He then opened eyes with Mesa in the Arizona Fall League, hitting .337 with one homer, four doubles, four triples and an .867 OPS in 21 games. With his bat-to-ball ability and impressive exit velocities, Hoerner could develop fast and grow into more power. MLB Pipeline listed him in the final spot in the latest Top 100 rankings and projected that he could reach MLB by the 2020 season. If Hoerner gets some Cactus League action this spring, Cubs fans will want to pay attention. -- Jordan Bastian

Pirates: Mitch Keller, RHP
Last year, Keller said it was "kind of a big deal" to pitch two innings in a mid-March Grapefruit League game. Pirates fans will get a much longer glimpse at the club's top prospect this spring. Keller, MLB Pipeline's No. 19 overall prospect, has been in big league camp from the start and may be preparing for his Major League debut at some point this summer, despite struggling in his first two spring starts. He has a plus fastball and curveball, and the Bucs have been stressing the importance of his changeup over the past few years. The 22-year-old right-hander is set to begin the season with Triple-A Indianapolis, where he initially struggled last season before finishing strong. Third baseman Ke'Bryan Hayes, Pittsburgh's No. 2 prospect and a dynamic defender with an improving bat, also is in big league camp for the first time this spring. -- Adam Berry

Reds: Nick Senzel, 3B/2B/OF
Cincinnati's prospect to watch happens to also be the organization's No. 1 prospect, according to MLB Pipeline, and MLB's No. 6 overall. Senzel is back for his second big league camp, but this one has much more at stake. The Reds have an opening in center field and Senzel -- a career infielder -- spent most of his offseason learning the position to try to make the team. Senzel could also make the club in a super-utility type role where he plays regularly. If the 23-year-old hadn't had a bout of vertigo and a broken right finger last season, he likely would already be in the Major Leagues. Now he must show not only that he can stay healthy, but that he can also be a quick learner to take on a new position at the game's highest level. -- Mark Sheldon

NATIONAL LEAGUE WEST

D-backs: Jazz Chisholm, SS
D-backs fans who got out to watch Arizona Fall League games last year got a sneak peek at Chisholm. Signed in the 2015 international class, Chisholm is an athletic shortstop who has moved up steadily through the system. While his ETA in the big leagues is probably not until 2020 and he could be one of the early cuts in camp, D-backs fans should take advantage of the opportunity this spring to get a glimpse of what the future looks like for the organization at shortstop. -- Steve Gilbert

Dodgers: Keibert Ruiz, C
Although his name came up in trade rumors involving J.T. Realmuto and others, Ruiz remains with the organization. While the Dodgers have some other attention-grabbing prospects, Ruiz is younger than outfielder Alex Verdugo or fellow catcher Will Smith -- and might also have the highest ceiling. Ruiz spent all last year at Double-A and is only 20 years old now. With Austin Barnes, Russell Martin, Rocky Gale and Smith ahead of him on the depth chart, the big question is how much spring playing time Ruiz gets. -- Ken Gurnick

Giants: Joey Bart, C
Bart, the Giants' top prospect, headlined the list of 18 non-roster invitees to big league camp this spring. The second overall pick out of Georgia Tech in last June's Draft, Bart quickly lived up to expectations after batting .298 with a .983 OPS and 13 home runs in 45 games with Class A Salem-Keizer in 2018. With Buster Posey on the mend from major hip surgery, the 22-year-old Bart is seeing some action early in camp, giving the Giants plenty of opportunities to evaluate their promising young catcher. -- Maria Guardado

Padres: Fernando Tatis Jr., SS
Who else? Tatis is presumably the answer to the Padres' decade-long shortstop question, with his presence shifting free agent acquisition Manny Machado back to third base. MLB Pipeline rated Tatis as the sport's No. 2 overall prospect, and he's the rare five-tool talent without a glaring flaw in his game. Tatis, who has only played a few months at Double-A, has his work cut out for him to make the Opening Day roster. He's got service-time concerns working against him as well. But he's going to arrive in San Diego soon enough. And he'll bring plenty of swagger with him. -- AJ Cassavell

Rockies: Brendan Rodgers, INF
Rodgers -- the No. 10 prospect in the Majors according to MLB Pipeline -- is in Major League camp for the second straight year, but this is his first shot at breaking with the big club as he competes for the starting second base job. Ryan McMahon, Garrett Hampson (the Rockies' No. 4 prospect) and Pat Valaika also are in the running for the job. Realistically, for Rodgers to not start the season at Triple-A Albuquerque, he'll have to win the job with a breakthrough spring -- like the one shortstop Trevor Story accomplished in 2016. -- Thomas Harding