Last season, Javier Baez and Blake Snell each went from being drafted outside the top 100 in most fantasy settings to becoming one of the best players in his respective leagues.
Fantasy owners who can pinpoint this year's versions of Baez and Snell will be in great position, but accomplishing that is easier said than done. The list below should help, as these 10 players have a good chance to make the leap from solid to spectacular in 2019.
• MLB.com's Top 800 fantasy rankings
Michael Conforto, OF, Mets
Key 2018 stat: Posted an .895 OPS after the All-Star break.
The fact that Conforto recorded a .216/.344/.366 slash line before the 2018 All-Star break is understandable, considering he underwent left shoulder surgery to repair a torn posterior capsule the previous September, didn't start swinging a bat again until January and made just eight plate appearances in Grapefruit League play. And yet, Conforto made his regular season debut April 5 after a brief stint on the injured list to open the season. In the second half, he more closely resembled his 2017 All-Star self, hitting .273/.356/.539 with 17 homers, 15 doubles and 52 RBIs in 68 games. Still just 25 years old, the outfielder could be ready for his best season yet.
Niko Goodrum, 1B/2B/3B/SS/OF, Tigers
Key 2018 stat: Was one of six players to record at least 15 homers and 10 steals in fewer than 500 plate appearances.
The list of 20/20 players from 2018 is replete with some of the top names in fantasy: Mike Trout, Mookie Betts, Jose Ramirez, Francisco Lindor, Christian Yelich, Trevor Story, Starling Marte, Baez. Goodrum could get there this season, with the added bonus of having eligibility at nearly every position on the diamond. The switch-hitter recorded 16 homers and 12 stolen bases in only 492 plate appearances last year, and his wheels -- his sprint speed of 29.1 ft/sec was well above the MLB average (27 ft/sec) -- make 20 steals a possibility.
Shohei Ohtani, DH, Angels
Key 2018 stat: 9.8 percent barrels/PA mark was MLB's sixth best (min. 150 batted-ball events).
The sheer novelty of watching Ohtani both pitch and hit last season overshadowed just how great he actually was at the plate. The lefty slugger showed a discerning eye (10.1 percent walk rate) and crushed the ball with regularity, leading to a .380 xwOBA. Despite tallying only 367 plate appearances, he finished with 22 homers and 10 steals. Ohtani has already been ruled out for Opening Day as he recovers from Tommy John surgery, but once he returns he'll get a chance to show what he can do while playing exclusively on offense.
Matt Olson, 1B, Athletics
Key 2018 stat: 52 percent hard-hit rate was MLB's fifth best among hitters (min. 150 BBE).
Compared to his 2017 rookie season, when he belted 24 home runs in just 216 plate appearances, Olson had a mildly disappointing 2018 campaign. Sure, he hit 29 home runs and recorded 84 RBIs, but his slash line (.247/.335/.453) left a lot to be desired, and his HR/FB rate was only 16.1 percent -- above average but hardly elite. Olson underwent surgery on his right hand in late March, which puts a damper on his fantasy stock, but he is worth stashing in all leagues. Given his penchant for smashing baseballs, the 24-year-old could have big things in store once he returns.
Amed Rosario, SS, Mets
Key 2018 stat: Had 18 steals in 64 games after the All-Star break.
Rosario still has major strides to make at the plate after hitting .256/.295/.381 with a 29-to-119 BB/K ratio in 2018, but at least he got more comfortable on the bases as the season progressed. Even though the youngster reached base at an unremarkable .302 clip after the All-Star break, his stolen-base pace in that span would equate to 46 steals over 162 games. Rosario tied for 23rd in the Majors with an average sprint speed of 29.4 ft/sec last year, so a 40-steal campaign isn't an unrealistic expectation in 2019.
José Alvarado, RP, Rays
Key 2018 stat: Was one of five pitchers with strikeout rate of 30 percent or higher and a ground-ball rate of at least 50 percent (min. 50 innings).
Alvarado is an example of how the term "breakout" can differ between the fantasy and non-fantasy realm. By most measurements, the left-hander broke out in 2018, recording a 2.39 ERA with 80 K's in 64 innings. This year, though, Alvarado is poised to take over as the Rays' primary closer. Attach 30-plus saves to Alvarado's other stats from last season -- which seem repeatable, given his skills -- and you have an elite fantasy closer.
Luis Castillo, SP, Reds
Key 2018 stat: Posted a 2.63 ERA in his final 14 starts.
Like Olson, Castillo took a step backward after a stellar rookie season. However, most of the damage was done against him in his first 17 starts, a span in which he registered a 5.85 ERA and yielded 18 home runs with 33 walks in 87 2/3 frames (1.8 HR/9, 3.4 BB/9). The rest of the way, Castillo notched a 1.1 HR/9 with a 1.8 BB/9 while recording a 2.63 ERA. Homer problems may persist, given the Reds' challenging home park, but Castillo has the stuff to overcome that.
Tyler Glasnow, SP/RP, Rays
Key 2018 stat: Posted an 8.4 percent walk rate after joining the Rays in a July trade (lifetime 13.9 percent before trade).
After acquiring him from the Pirates as part of the package for Chris Archer, the Rays unlocked the version of Glasnow that once made him a consensus top 20 prospect. Most importantly, the flamethrowing righty put fewer men on base via the free pass while continuing to miss bats (28.4 percent strikeout rate with TB). The Rays like to get creative with their pitching staff, but Glasnow could nonetheless challenge the 150-inning mark, as Ryan Yarbrough did in 2018 (147 1/3 IP).
José Leclerc, RP, Rangers
Key 2018 stat: 20 percent hard-hit rate was MLB's best among pitchers (min. 100 batted-ball events)
Leclerc can be put in the same category as Alvarado in that he broke out in a traditional sense last season, recording a 1.56 ERA with a 0.85 WHIP and a 13.3 K/9 mark. Now, he's ready to become a fantasy star. Leclerc took over as the Rangers closer last August after Keone Kela was dealt to the Pirates, and he was sensational, going 12-for-12 in save chances while allowing nary a run and fanning 29 batters in 18 innings. The righty was so good that new manager Chris Woodward has already named him the Rangers closer to begin 2019. Leclerc should be drafted as a top 10 fantasy reliever, and he could vault to the top five, a la Edwin Diaz in 2018.
Joey Lucchesi, SP, Padres
Key 2018 stat: 3.45 xFIP ranked 23rd in MLB (min. 130 innings).
Lucchesi made the jump from Double-A to the Majors and showed the potential to be a rotation staple for the Padres in 2018, recording a 145-to-43 K/BB ratio in 130 innings. He struggled to limit homers, however, and finished with an unremarkable 4.08 ERA (94 ERA+) as a result. Improvement could be on the horizon, though, as Lucchesi should see his HR/FB rate drop significantly. Lucchesi's 20.4 percent HR/FB mark was not only well north of the MLB average (12.7 percent), but also the highest in the Majors among those who threw at least 130 innings last season. Four hurlers posted a HR/FB rate above 20 percent in 2017 while tossing at least 130 innings; the three who pitched in the big leagues last season all saw their HR/FB rates drop by more than three percentage points.