Fantasy Baseball 2020: Predicting Biggest Sleepers and Breakout Stars

One hallmark of success in Major League Baseball and fantasy baseball is the unexpected surprise on the roster. 

If someone had said prior to the start of last season that Oakland A's shortstop Marcus Semien would rank fifth among all MLB players with 7.6 FanGraphs wins above replacement, you could be forgiven for thinking they were foolish. 

A deep dive into his 2018 stats did show the potential for big things. He had his lowest strikeout rate (18.7 percent), highest hard-hit percentage (32.5) and second-highest line-drive rate (22.8 percent) of his career at that point.

That didn't guarantee Semien would turn in a 2019 campaign with 33 homers, .285 average, 123 runs scored and 92 RBI, but there were indicators working in his favor. 

Using a number of standard and advanced stats, here are the sleepers and breakout stars to keep an eye on for your fantasy team in 2020. 

Nick Solak, IF/DH, Texas Rangers

A cup of coffee at the end of last season turned into Nick Solak forcing his way into the Texas Rangers' plans whenever the 2020 campaign begins. 

After being promoted to the big leagues on Aug. 20, the 25-year-old posted a .293/.393/.491 slash line with five homers in 33 games. E

Even though Solak's .354 batting average on balls in play suggests some regression could be coming, he had at least a .330 BABIP in all four levels of the minors. 

Another thing Solak did throughout the course of his minor league career was hit. He owns a .294/.383/.468 slash line with 61 homers in 435 games from 2016-19. 

His bat is going to carry him in the big leagues, as he doesn't have a defined defensive position. Evan Grant of the Dallas Morning News noted in February the Rangers were working with the former Louisville star in center field, with the possibility of using Danny Santana off the bench. 

One encouraging sign moving forward is Solak has dramatically increased his power output. He hit 32 homers between Triple-A and MLB last season after hitting 12 homers in his first full professional season two years earlier. 

As long as he is able to win a starting job out of camp, he's got the offensive profile to be a valuable fantasy player in 2020. 

Per FantasyPros, Jorge Soler is going more than 200 spots ahead of Solak (84.4 to 294.6). The Kansas City Royals man is coming off a career year with 48 homers, but it was also the first time he stayed healthy enough to play more than 100 games since 2015. 

Given the uncertainty around Soler being able to stay on the field, Solak has the potential to be a better fantasy asset this season. 

Aaron Civale, SP, Cleveland Indians

When the Cleveland Indians traded Corey Kluber to the Rangers in December, it was a signal that they saw enough from Aaron Civale's late-season performance to plug him into their rotation in 2020. 

In 10 starts, the 24-year-old went 3-4 with a 2.34 ERA, 46 strikeouts, 44 hits, 16 walks and four homers allowed. Those numbers are well in line with what the right-hander did in four minor league seasons (3.12 ERA, 317 strikeouts, 32 homers allowed in 381.1 innings). 

Another reason to be optimistic about Civale being able to carry those 2019 numbers over is the team he plays for. The Indians have a strong case as the best developmental organization for starting pitchers.

Their list of success stories includes current and former All-Stars Kluber, Carlos Carrasco, Mike Clevinger, Trevor Bauer and Shane Bieber. 

Bieber's trajectory might tell fantasy players a lot about what they can expect from Civale. Bieber's rookie season in 2018 was a mixed bag with a 4.55 ERA, 130 hits allowed and 118 strikeouts in 114.2 innings. 

The Indians took the pieces that worked from Bieber's first year, developed some additional elements—Keith Law wrote on ESPN.com last September that the right-hander found five more inches of horizontal break on his changeup and 43 percent of his swings and misses came from his slider. 

Civale isn't fastball-dependent, throwing it only 38.5 percent of the time last season. His cutter and slider accounted for 44 percent of his pitches.

If he continues to pound the strike zone with the fastball as he did last season and creates more bite with his cutter and slider, the Indians could have another All-Star starting pitcher on their hands. 

Adam Eaton, OF, Washington Nationals

Despite being a known quantity, Adam Eaton appears to be flying well below the fantasy radar for the 2020 season. 

Per Fantasy Pros, the 31-year-old's current average draft position of 204.0 is behind Lorenzo Cain (181.6) and Yasiel Puig (182.6). 

Cain is coming off a 2019 in which he posted a .697 OPS, his second-lowest in a single season in which he played at least 100 games (.658 in 2013). 

Puig had a decent fantasy season in 2019 with a .267 batting average, 24 homers, 84 RBI and 19 stolen bases in 149 games between the Indians and Cincinnati Reds. He's also unemployed at the moment, as no teams have signed the free-agent outfielder. 

Eaton, on the other hand, is gainfully employed by the Nationals and coming off another productive season. He posted a .279/.365/.428 slash line with a career-high 15 homers and 15 stolen bases. 

Even though Eaton isn't a game-changer for your roster, given his current draft position and the players going ahead of him, taking a flyer on him in the later rounds as an outfielder who can do a bit of everything makes him a valuable asset.