As Spring Training gets underway, MLB.com has taken a closer look at prospects getting the chance to show what they can do in the Grapefruit and Cactus Leagues. For example, there's been a story on 20 prospects likely to be impact rookies during the 2019 season.
Our beat writers also singled out one prospect to watch in each big league camp. But that didn't necessarily focus on prospects vying for Opening Day jobs. The 30 prospects below all are getting very long looks this spring with an eye toward breaking camp with the parent club. Even if they start the year in the Minors, they all should get the chance to contribute at some point in the very near future.
American League East
Blue Jays: Vladimir Guerrero Jr., 3B (No. 1 on Top 100 Prospects list)
Guerrero probably won't land on the Blue Jays' Opening Day roster as the club looks to retain an extra year of control over one of the best prospects in history. However, it almost goes without saying that the 20-year-old third baseman is ready to make an impact in the big leagues after he led the Minors in average (.381), slugging (.636) and OPS (1.073) in 2018. With his 80-grade bat and potential to hit 35-plus homers, Guerrero should become one of the sport's premier talents in short order.

Orioles: Richie Martin, SS
Left off the A's 40-man roster despite his breakout 2018 season in Double-A, the '15 first-rounder became the first selection in the Rule 5 Draft in December. A plus defender who runs well and hits for average, albeit without much pop, Martin is penciled in as the Orioles' Opening Day shortstop right now, and he does enough things well to stick on the active roster in a reserve role.
Rays: Brandon Lowe, 2B/OF 
Breaking out in earnest in 2018, Lowe slugged his way up to Triple-A and hit 14 homers there to earn his first big league callup in August. With the Rays, he overcame an 0-for-19 start to his career to finish with six home runs and a .774 OPS in 129 at-bats, keeping his prospect status in place. Given Tampa Bay's emphasis on defensive versatility, Lowe, with his ability to play both second base and the outfield, is a candidate to get regular at-bats in '19.
Red Sox: Colten Brewer, RHP
In search of low-cost bullpen options, Boston acquired Brewer from the Padres in November in exchange for second-base prospect Esteban Quiroz. Brewer has a difference-making pitch in a 92-96 mph fastball with tremendous natural cut, and he also has a power curveball that he doesn't always land for strikes.
Yankees: Jonathan Loaisiga, RHP (MLB No. 66)
New York doesn't have an obvious rotation opening after trading for James Paxton and re-signing J.A. Happ and CC Sabathia. But Loaisiga impressed at times during his big league debut last summer and has three pitches (fastball, curveball, changeup) that grade as plus or better when at their best.
AL Central
Indians: Yu Chang, SS/3B
Chang is not going to dislodge Francisco Lindor from shortstop, but he is capable of playing second and third base and winning at least a utility role this spring. He could approximate the production Cleveland gets out of Jason Kipnis at second base for a fraction of the veteran's $14.5 million salary.
Royals: Richard Lovelady, LHP
The Royals do have a pair of Rule 5 Draft picks in Sam McWilliams and Chris Ellis, and we know they like to keep those guys, as well as hard-throwing prospects like Josh Staumont. But Lovelady's funky delivery and potential to have three very usable pitches gives him the chance to get some high-leverage innings very soon.
Tigers: Christin Stewart, OF
The second of Detroit's two first-round picks in 2015, Stewart reached the Majors for the first time last September after hitting 93 home runs in 460 Minor League games. He homered twice in the big leagues, hitting both as part of a multihomer performance against the Royals, and he impressed with an approach that has improved in every season. While his limitations on defense suggest that Stewart will likely see most of his time as a DH, he has the combination of massive raw power and on-base skills to stick in the role.
Twins: Stephen Gonsalves, LHP
Gonsalves' first taste of the big leagues didn't go so well last year, but the hope is the adversity he faced there, along with some mechanical tweaks he's made, will help him going forward. The Twins' rotation is crowded, but look for this lefty to help out at some point in 2019.
White Sox: Eloy Jiménez, OF (MLB No. 3)
Jimenez not only should win a corner-outfield job with the White Sox, but he also should be their best offensive player as a rookie. While the No. 3 overall prospect may have his arrival in Chicago further delayed by service-time considerations, he's ready to rake after batting .337/.384/.577 with 22 homers in the upper Minors a year ago.

AL West
A's: Jesus Luzardo, LHP (MLB No. 12)
A lot of eyes are on the top lefty pitching prospect in baseball, as he is being given every chance to make the A's rotation this spring. Keep in mind, though, he's only made four starts above Double-A, so a little seasoning could be in order. Expect him to pitch well enough in Cactus League games to make the decision very tough.

Angels: Ty Buttrey, RHP
The Angels clearly liked Buttrey enough to get him in the Ian Kinsler trade with the Red Sox last summer, but they were more impressed with his complete repertoire than they anticipated. In addition to his outstanding fastball, he has the chance to have two excellent secondary pitches, which points to a future pitching late in games.
Astros: Josh James, RHP (MLB No. 62)
A 34th-round pick out of Western Oklahoma JC in 2014, James broke out last year by leading the Minors in strikeout rate (13.5 per nine innings) and claiming a spot on Houston's postseason roster. He misses bats with three pitches and should open the season in the Astros' rotation provided he throws enough strikes.
Mariners: Justus Sheffield, LHP (MLB No. 43)
The M's acquired Sheffield in the Paxton deal with the expectation he'd contribute to the rotation in 2019. If everyone is healthy, Seattle has a set five ready to go, but the young lefty will get a long look and could break through with a strong spring, or at least be ready to be the first one to answer the bell when there's a need.
Rangers: C.D. Pelham, LHP
Pelham rocketed from Class A Advanced to Texas last year and has the highest upside of any of the left-handed relievers on the club's 40-man roster. With a fastball that can reach the upper 90s and a cutter that can be unhittable at times, he just needs to throw strikes to become a late-inning force.
National League East
Braves: Touki Toussaint, RHP (MLB No. 50)
So many pitchers, so little room. A number of pitching prospects who contributed to the Braves' playoff push will get innings in Florida, with Mike Soroka, Kyle Wright and Bryse Wilson coming most to mind. Toussaint, though, made a lasting impression and landed on the postseason roster, giving him a small leg up.
Marlins: Sandy Alcantara, RHP
Alcantara might have the best stuff of any of Miami's rotation candidates, though he still needs to prove he can harness it on a regular basis. He can reach triple digits with his fastball and carve up hitters with his slider and curveball when they're working.
Mets: Peter Alonso, 1B (MLB No. 51)
After he tied for the Minor League lead with 36 homers and led it outright with 119 RBIs in 2018, Alonso enters the season with nothing left to prove in the Minors. There was clamoring from fans for the Mets to promote him late last season, and that is likely to carry over into Spring Training. The Mets must keep Alonso in the Minors until mid-April if they want to ensure an extra year of team control, though with the organization seemingly in win-now mode, a spot on the Opening Day roster could be a possibility.

Nationals: Victor Robles, OF (MLB No. 4)
After making his debut in the big leagues as a 20-year-old and then winning a spot on the Nationals' postseason roster in 2017, Robles appeared poised for an everyday role in the team's outfield last season until a hyperextended left elbow in April derailed his progress, landing him on the injured list for three months. Robles should finally get his chance as the Nats' center fielder in 2019, and has the type of across-the-board tools -- headlined by top-of-the-scale speed and defense -- that could make him an impact player in all facets of the game.
Phillies: Enyel De Los Santos, RHP
The Phillies have some pitching depth amassing at the top of the system, with lefties like Ranger Suárez, JoJo Romero and Cole Irvin all just about ready to help out. De Los Santos chipped in last year and has the stuff that would fit well out of the bullpen if that's where the need is in Philadelphia.
NL Central
Brewers: Keston Hiura, 2B (MLB No. 20)
The No. 9 pick in the 2017 Draft, Hiura raked his way up to Double-A in his first full season, then garnered MVP honors in the Arizona Fall League after he led the circuit in RBIs. The Brewers likely will send Hiura, a plus hitter with plus power potential, to the Minors to begin the season so as to offer him more upper-level experience. However, second base has also been a black hole of production for the club in recent years, and there's no better prospect at the keystone in the Minors than Hiura.
Cardinals: Alex Reyes, RHP (MLB No. 33)
After Tommy John surgery cost him all of 2017 and delayed the start of his campaign in '18, Reyes, the Cardinals' top prospect in each of the past four years, returned to the Majors last June, only to leave his first start with a torn tendon in his lat muscle that required season-ending surgery. His rehab schedule has him on track to pitch during Spring Training, and if he proves to be healthy, Reyes, with his power stuff and knack for missing bats, would be a welcome addition to the Cards' Opening Day rotation.

Cubs: Dakota Mekkes, RHP
Mekkes led NCAA Division I in hit rate (4.1 per nine innings) and strikeout rate (15.2) at Michigan State in 2016, and has put up similarly crazy numbers in three years as a pro: 1.16 ERA, 5.3 hits and 11.6 strikeouts per nine innings. He succeeds largely on the basis of a low-90s fastball that plays way above its velocity because of his extension and deception, just the kind of different look that would fit nicely in the middle innings for the bullpen-needy Cubs.
Pirates: Kevin Newman, SS
Jordy Mercer is gone, so there will be competition for the shortstop gig in Pittsburgh. Most think Erik González will be the guy, but Newman will get the chance to win it and push Gonzalez to a utility role. The former first-round pick has hit in the Minors, but looked overmatched during his brief big league debut last year.
Reds: Nick Senzel, OF (MLB No. 6)
Senzel was primarily a third baseman. Then he saw time at second. Now he's learning how to play center field. Even though injuries curtailed Senzel's 2018 season, the Reds think Senzel's bat is just about ready, so they're trying to find a spot for it in their lineup, and center might be the best opportunity right now.
NL West
D-backs: Yoan Lopez, RHP
Signed by Arizona for more than $8 million in 2015, Lopez overcame a host of struggles early in his career, both on and off the field, to put it all together in '18. He made the jump from Double-A, where he had averaged 12.7 K/9, to the Majors in September and showcased electric stuff out the D-backs' bullpen, pairing a fastball that reached 99 mph with a wipeout mid-80s slider.
Dodgers: Alex Verdugo, OF (MLB No. 35)
One of the best pure hitters in the Minors, Verdugo has batted .321 in Triple-A the past two seasons as one of the youngest regulars in the Pacific Coast League. But Los Angeles still has a logjam of outfielders, even after trading Matt Kemp and Yasiel Puig to the Reds, so he faces an uphill battle.
Giants: Chris Shaw, OF
No Giant managed more than 16 home runs last year, a total Shaw easily could top if he wins San Francisco's wide-open left-field job. He has averaged 23 homers in three full Minor League seasons and his first big league shot was a 468-foot blast off Seunghwan Oh last September.
Padres: Francisco Mejía, C (MLB No. 26)
Acquired from the Indians at last year's All-Star break for relievers Brad Hand and Adam Cimber, Mejia slashed .328/.364/.582 with seven homers in 31 Triple-A games after the trade before joining the Padres in the big leagues as a September callup. He's an advanced switch-hitter who makes a lot of hard contact from both sides of the plate, though his defense is inferior to Austin Hedges'.

Rockies: Brendan Rodgers, INF (MLB No. 10)
With DJ LeMahieu signing a free agent deal with the Yankees, second base is up for grabs in Colorado. Rodgers, who has seen time at three infield spots in the Minors, joins fellow prospect Garrett Hampson and recently graduated prospect Ryan McMahon among those competing for the job. He might start the year in Triple-A, but look for him to hit his way back up quickly.