When it comes to prospects, part of the fun is trying to identify the next breakout star before he becomes a highly touted, well-known name. Those prospects are often flying under the radar, either because they are coming off injuries, haven't performed up to expectations or are just beginning their pro careers.
With 2019 around the corner, MLB Pipeline has picked one of these types of prospects from each organization as a potential breakout candidate. Some of the names below might be more familiar than others, but they all could jump on the scene during the upcoming season and establish themselves as exciting prospects.
American League East
Jean Carlos Encarnacion, 3B, Orioles No. 15
Encarnacion has the highest ceiling of the four prospects that the Orioles acquired in the deal that sent Kevin Gausman to the Braves at the non-waiver Trade Deadline. The 20-year-old has prototypical third-base tools, as he's already physically strong and knows how to impact the baseball. He offered a glimpse of his potential last year (in his first full season) by slashing .273/.298/.439 with 12 home runs and 46 extra-base hits over 123 games in the South Atlantic League. Those numbers should improve in 2019, provided he can trim his 27.7 percent strikeout rate.
Darwinzon Hernandez, LHP, Red Sox No. 7
Hernandez followed up a strong regular season with an impressive performance in the Arizona Fall League. While the 22-year-old struggled with command -- an issue that has plagued him throughout his career -- walking 66 over 107 innings this year, he racked up 134 strikeouts. In the AFL, Hernandez pitched out of the bullpen -- where his fastball-slider combination can form a dominant pairing -- and yielded only three runs (two earned) over 11 1/3 innings.
Albert Abreu, RHP, Yankees No. 3 (MLB No. 85)
Abreu has impressed when he's been on the mound, but keeping him there has been a bit of an issue. The hard-throwing right-hander has missed time with a shoulder strain, an appendectomy and elbow inflammation over the past two seasons, and was on the disabled list twice in 2018. If healthy in '19, Abreu has three pitches -- a fastball, breaking ball and changeup -- that all grade out as plus and could help him quickly climb through the Yankees' system.
Shane Baz, RHP,Rays No. 6
Acquired from the Pirates as the player to be named later in the Chris Archer Trade Deadline deal, Baz underwhelmed statistically last season in the rookie-level Appalachian League, pitching to a 4.47 ERA, 1.62 WHIP and 59/29 strikeout-to-walk ratio over 52 1/3 innings (12 starts). He still impressed with his raw stuff, utilizing a four-pitch mix that included a low- to mid-90s fastball and three secondaries that project to be above-average or better. Evaluators expect better results from Baz going forward as the young righty's control improves and he refines his breaking balls.
Nate Pearson, RHP, Blue Jays No. 4 (MLB No. 90)
After his brilliant pro debut in 2017, Pearson's first full season came to an abrupt end when he was struck by a line drive and sustained a broken right ulna 1 2/3 innings into his first start at Class A Advanced Dunedin. He was rusty when he returned to the mound in the Arizona Fall League, and struggled initially, before settling in and dominating during the season's final weeks. When he was right, Pearson showed top-of-the-rotation potential, with a legitimate triple-digit fastball, a plus slider and feel for both a curveball and changeup.
Luis Robert, OF, White Sox No. 4 (MLB No. 44)
Robert's five-tool potential has never been questioned. However, his enticing skillset has hardly been on display as injuries have hampered his brief career. Robert missed time with minor injuries in 2017, then played only 50 games in '18 after injuring the ligaments in his thumb. Robert showed flashes of potential in the Arizona Fall League, where he hit .324 with two homers, but again missed a few games with a minor injury. If Robert can stay healthy in 2019, there's a good chance he will post huge numbers.
George Valera, OF, Indians No. 5
Signed for $1.3 million in July 2017, Valera carried plenty of hype into his pro debut and got off to a strong start in the rookie-level Arizona League, only to have his season end after six games due to a broken hamate bone in his hand and subsequent surgery. The injury has done nothing to diminish the 18-year-old outfielder's upside, and scouts continue to rave about Valera's gorgeous left-handed swing as well as his ability to apply his power during games at a young age.
Jose Azocar, OF, Tigers No. 19
Azocar's tools have long been tantalizing, and every time he's appeared poised to take a step forward, he's gone backward. He still needs to refine his overall approach at the plate, but he cut his strikeout rate considerably in 2018, perhaps a sign he's ready to head consistently in the right direction.
Kyle Isbel, OF, Royals No. 14
Isbel took a leap forward during his junior season at UNLV, before the Royals took him in the third round of the 2018 Draft. The 21-year-old carried that momentum into his professional debut, where he hit .326 with seven homers over 64 games. Isbel finished the year with Class A Lexington, and his initial success, along with his compact swing and patient approach, could be foreshadowing a big full-season debut in '19.
Yunior Severino, 2B/SS, Twins No. 21
Severino was one of the Braves' prospects who was declared a free agent in the wake of the organization's international rules violations. He signed with the Twins and had a solid 2018 season in the rookie-level Appalachian League. There's considerable offensive upside here, with the chance to hit for both average and power from both sides of the plate.
Bryan Abreu, RHP, Astros No. 10
Abreu notched 90 strikeouts in 54 1/3 innings this season and could be in store for another big year as he continues to refine his command and work his way through the system. Abreu has thrown only 38 1/3 innings at the full-season level, but with a fastball that sits at 92-94 mph and a curveball that some executives feel is the best in the system, it's easy to see why 2019 could be a big year for Abreu.
Livan Soto, SS, Angels No. 16
Another Braves prospect who was made a free agent, Soto had a solid organizational debut with the Angels in the Pioneer League in 2018, hitting .291. It's his advanced approach at the plate (.385 on-base percentage, 24/24 K/BB), not to mention his defensive prowess, that bodes well for his future.
Sean Murphy, C, Athletics No. 3 (MLB No. 47)
Murphy might have reached the Majors last year if not for a broken hamate bone and subsequent hand surgery in July while in Double-A, which sidelined him for about six weeks. Although Murphy's stellar defense behind the plate is a known commodity and will make him an everyday big league catcher in short order, it's his remaining development as a hitter that makes him a breakout candidate for 2019. The 24-year-old has tools to impact the game offensively, with a line-drive-oriented swing, above-average raw power and advanced feel for the strike zone.
Jake Fraley, OF, Mariners No. 27
Fraley tore up the Australian Baseball League (1.130 OPS, 13 homers, 39 stolen bases in 40 games) last offseason, but missed the first two months of the 2018 regular season with a toe injury. When he finally got going in June, the left-handed-hitting outfielder posted a .347/.415/.547 line with 30 extra-base hits and 11 steals over 66 games in the Florida State League. That performance put him on the Mariners' radar, and the club was thrilled to land him, along with Mallex Smith, this offseason in the Mike Zunino trade. With a swing that features natural loft, Fraley is a great candidate to break out in '19. However, he'll need to stay on the field to do so after totaling only 151 games across his first three pro seasons.
Hans Crouse, RHP, Rangers No. 4
Crouse's first full season was certainly a success, and something the Rangers hope was a sign of things to come. The 20-year-old posted a 2.47 ERA across two levels and recorded 62 strikeouts and 19 walks in 54 2/3 innings (13 starts). Crouse, who has a slightly unconventional delivery, features a mid-to-upper-90s fastball and a wipeout slider. The right-hander also has a changeup that has the potential to be an average third pitch.
Freddy Tarnok, RHP, Braves No. 18
That's right, another Braves pitching prospect. Atlanta went way over pick value to sign Tarnok in the third round of the 2017 Draft. He pitched well out of the bullpen in the first half of 2018 (1.26 ERA in 16 games) and scuffled a bit as a starter. But as someone who didn't pitch until his junior year of high school, his ceiling as a future starter is very high.
Isan Diaz, 2B, Marlins No. 9
After joining the Marlins from the Brewers in last offseason's Christian Yelich blockbuster, Diaz, in his age-22 season, produced a .771 OPS with 13 home runs over 119 games between Double-A and Triple-A. Power is Diaz's calling card -- he's hit at least 13 homers in each of the past four years, highlighted by a career-high 20 homers during his 2016 full-season debut -- as he's long impressed evaluators with his ability to drive the ball out of the park to all fields with a Robinson Cano-esque swing. That power could be on display in Miami next season, after the club added Diaz to its 40-man roster.
Ronny Mauricio, SS, Mets No. 6
First, there was Amed Rosario. Next up is top Mets prospect Andres Gimenez. On his way is Mauricio, who signed for $2.1 million in July 2017, and had a strong debut in the Gulf Coast League in '18, until he wore down. He has tools on both sides of the ball and is just starting to figure out how to use all of them.
Francisco Morales, RHP, Phillies No. 13
Morales wasn't as impressive in the New York-Penn League in 2018 as he was during his GCL debut the year prior, but his stuff is still plenty good. He continued to miss a lot of bats (10.9 K/9 in '18) and needs to refine his command to take the next step, perhaps as a teenager in full-season ball for the first time.
Jake Irvin, RHP, Nationals No. 17
The Nats' fourth-round pick from 2018 was sharp during his pro debut, posting a 1.74 ERA with a .211 batting average against over 20 2/3 innings between the rookie-level Gulf Coast League and short-season Class A Auburn. As a durable 6-foot-6, 225-pound righty with a solid three-pitch mix, Irvin has the necessary ingredients to move quickly through the Minors in his first full season, and the potential to develop as a back-of-the-rotation starter.
Cole Roederer, OF, Cubs No. 14
Roederer, the Cubs' supplemental second-round pick from the 2018 Draft, got off to a fast start in the rookie-level Arizona League, hitting .275/.354/.465 over 36 games in his professional debut. The 19-year-old has a mature offensive approach and an ability to hit the ball to all fields, and if his stint in the AZL was any indication, he could be in store for a big first full season.
Jeter Downs, SS/2B, Reds No. 7
The Reds selected Downs with the No. 32 overall pick in the 2017 Draft out of the Florida high school ranks, and he responded with a solid first full season in '18 that included 13 home runs and 37 steals. There's more pop to come as he refines his approach, with the possibility of 20-20 seasons.
Tristen Lutz, OF, Brewers No. 5
The No. 34 overall pick from the 2017 Draft showed a dynamic bat in his first full season as he totaled 13 homers and 33 doubles (with a 45 percent extra-base-hit rate) in the Midwest League. While Lutz struck out quite a bit in the process, he still demonstrated a solid approach, as well as pitch-recognition skills that will only improve as he gains experience. With a blend of size, athleticism, tools and baseball skills, Lutz has one of the higher ceilings in Milwaukee's system and could emerge as one of baseball's premier young outfield prospects in 2019.
Cole Tucker, SS, Pirates No. 5
Tucker's full season in Double-A was decent enough, but it's the fact that his second-half OPS was 145 points higher than his first half, combined with his .370 Arizona Fall League average and .442 OBP (third and fourth in the AFL, respectively), that makes him a good candidate to put it all together in 2019.
Elehuris Montero, 3B, Cardinals No. 7
In many ways, Montero broke out in 2018, hitting .322/.381/.529 with 15 homers in the Midwest League to earn a promotion to the FSL before he turned 20. Still learning to tap into his raw power, the third baseman should become more of a known name on the national prospect landscape in '19, especially if he can avoid hitting in Palm Beach's hitting haven and jump to Double-A.
Kristian Robinson, OF, D-backs No. 12
The D-backs spent $2.5 million to sign Robinson out of the Bahamas in July 2017. In his first full pro season in '18, he hit well enough to earn a promotion from the Arizona League to the Pioneer League, where he held his own. He has tremendous raw power that he should continue to learn to tap into in 2019.
Tyler Nevin, 1B/3B, Rockies No. 11
Nevin put together the best offensive season of his career (.328/.386/.503) over 100 games with Class A Advanced Lancaster during the 2018 campaign. However, Lancaster is an extremely hitter-friendly environment, which may have made some wary of those numbers. If they were, Nevin helped ease those concerns with a .426 average over 17 games in the Arizona Fall League, and he will look to build on that success as he likely moves up to Double-A in '19.
Michael Grove, RHP, Dodgers No. 12
Grove, the Dodgers' second-round pick in 2018, missed all of last season while recovering from Tommy John surgery. When healthy, the right-hander has a pair of plus pitches -- a fastball that sits in the low-to-mid 90s and a high-spin-rate slider with tremendous depth. Grove's control improved during his time at West Virginia, but there is still room for improvement as he continues to develop. Grove has yet to make his professional debut and will be coming off Tommy John, so it's unlikely the Dodgers are super aggressive with him, but the 2019 season could be a big one for Grove.
MacKenzie Gore, LHP, Padres No. 2 (MLB No. 13)
Gore, the No. 3 pick from the 2017 Draft, was limited by a recurring blister issue during his first full season and logged only 60 2/3 innings, posting a 4.45 ERA with 74 strikeouts and 18 walks over 16 starts. The 19-year-old southpaw's stuff and overall feel were still plenty good, though, and there's reason to believe he'll be even better once fully healthy, with a chance to move relatively quickly, in 2019.
Heliot Ramos, OF, Giants No. 2 (MLB No. 74)
Ramos has the highest ceiling of anyone in the Giants' system, but a lack of patience at the plate has resulted in some struggles early in his career. Ramos, 19, led the rookie-level Arizona League in slugging (.645) in his 2017 pro debut, but that number dipped to .396 over 124 games with Class A Augusta in '18. Ramos has well-above-average power, but he struck out 136 times in 124 games a season ago. If Ramos can make more contact, allowing him to tap into his power more, his future is bright.
William Boor is a reporter for MLB Pipeline. Follow him on Twitter at @wboor.
Jonathan Mayo is a reporter for MLB Pipeline. Follow him on Twitter @JonathanMayo and Facebook, and listen to him on the weekly Pipeline Podcast.
Mike Rosenbaum is a reporter for MLB.com. Follow him on Twitter at @GoldenSombrero.