Top 20 MLB Rookies Entering 2021
Even in a shortened 2020 season, rookies made an enormous impact.
Kyle Lewis and Luis Robert put on shows in center field in the American League, while Cristian Javier helped carry a wounded Astros' rotation within a game of the World Series. Devin Williams and his “airbender” changeup made history in the National League, while Jake Cronenworth, Dustin May and Tony Gonsolin also played key roles in getting their teams to the playoffs, to say nothing of the offensive show Alec Bohm put on after his callup.
One unique consequence of the shortened season was that many players who played key roles for their teams remain rookie eligible in 2021. Randy Arozarena, Ke’Bryan Hayes, Sixto Sanchez, Ian Anderson and Ryan Mountcastle all ranked among the best rookies in baseball in 2020 and still retained their rookie eligibility for 2021.
What those players—and many others—will do for an encore is one of the most compelling storylines of the season.
Here are Baseball America’s top 20 rookies for 2021, as selected by the staff. Capsules are written by Kyle Glaser. All players are listed with their age on Opening Day.
1. Randy Arozarena, OF, Rays
Age: 26 | Projected Role: LF
Notable number: 15
The number of Arozarena’s 18 career home runs in the regular season and postseason that have come off fastballs.
Arozarena hit 10 home runs last October, the most ever in a single postseason, to set the baseball world aflame and lead the Rays to the World Series last year. While he certainly won’t hit .377 or average a home run every other game over a full season—as he did in the playoffs—his long track record of hitting, growing power and electrifying athleticism should help him remain one of baseball’s top young hitters.
2. Ke’Bryan Hayes, 3B, Pirates
Age: 24 | Projected Role: 3B
Notable number: 1.124
Hayes’ OPS last September, which ranked fourth in the major leagues.
Long renowned for his glove, Hayes finally caught up with his bat and hit .376/.442/.682 in a scorching 24-game debut last season. He will open the year as the Pirates’ starting third baseman and, if he can maintain his offensive strides, has the combination of Gold Glove-caliber defense, above-average speed and offensive potential to be a cornerstone of Pittsburgh’s rebuild.
3. Dylan Carlson, OF, Cardinals
Age: 22 | Projected Role: RF
Notable number: .967
Carlson’s OPS last season from the start of his second callup through the postseason.
Carlson shook off a rocky first stint in the majors to finish the year strong and became just the third Cardinals player age 21 or younger to bat cleanup in the postseason, joining Stan Musial and Albert Pujols. The offseason trade of Dexter Fowler opens up right field for Carlson, whose patient approach, ability to make hard contact from both sides of the plate and above-average speed should make him a valuable contributor.
4. Sixto Sanchez, RHP, Marlins
Age: 22 |Projected Role: SP
Notable number: .148
Opponent average and slugging percentage against Sanchez in at-bats ending with a changeup last season.
Sanchez flashed high-octane stuff in his eye-popping debut last season, highlighted by throwing five scoreless innings at Wrigley Field in his first postseason start. With a 97-101 mph fastball, a devastating changeup, an improving breaking ball and exceptional control for a power pitcher, Sanchez has secured his place in the Marlins’ rotation and has a chance to be a frontline starter.
5. Ian Anderson, RHP, Braves
Age: 22 | Projected Role: SP
Notable number: Nine
Earned runs Anderson allowed in 10 starts last year between the regular season and postseason.
If not for Arozarena, Anderson would have been the star rookie of the 2020 postseason. After logging a 1.95 ERA in the regular season, he opened the playoffs with 15.2 consecutive scoreless innings and got the start in Game 7 of the National League Championship Series versus the hard-hitting Dodgers. With three quality pitches and uncanny poise for his age, he is set to join Mike Soroka and Max Fried as young studs at the front of Atlanta’s rotation.
6. Alex Kirilloff, OF, Twins
Age: 23 | Projected Role: LF
Notable number: 71
The minor league-leading total of extra-base hits Kirilloff had the last time he played a full season in 2018.
Kirilloff became the third player to make his major league debut in the postseason last year and promptly recorded his first hit. With a sweet lefthanded swing, the precocious young outfielder batted .317/.365/.498 in his minor league career and is widely regarded as one of the best pure hitting prospects in baseball. After Eddie Rosario was non-tendered in the offseason, left field is open for Kiriloff to take over in 2021.
7. Ryan Mountcastle, OF, Orioles
Age: 24 | Projected Role: LF
Notable number: .474
Mountcastle’s batting average against fastballs 95 mph and faster in 2020.
Mountcastle has bounced from shortstop to third base to first base to left field in his career, but no matter where he’s played, he’s hit. After winning MVP of the Triple-A International League in 2019, Mountcastle made his major league debut in 2020 and hit .333/.386/.492 in a sizzling first impression. With the Orioles still entrenched in their rebuild, Mountcastle has already solidified his place in the middle of Baltimore’s lineup.
8. Nate Pearson, RHP, Blue Jays
Age: 24 | Projected Role: SP
Notable number: 101.5
Pearson’s peak velocity in miles per hour last season, tying him for 10th fastest for a single pitch.
Pearson battled control issues and elbow tightness in his big league debut, but he showed how dominant he could be when he struck out five of the six Rays batters he faced in Game 2 of the American League Wild Card Series—all swinging. He suffered a groin injury in spring training, but he’ll join the Blue Jays rotation once he’s healthy and should be one of their top starters.
9. Jarred Kelenic, OF, Mariners
Age: 21 | Projected Role: LF
Notable number: .904
Kelenic’s OPS as he jumped three levels to Double-A in 2019, a year after being drafted out of high school.
Kelenic raced to Double-A in his first full season and performed well at the Mariners’ alternate training site in 2020. Former team president and CEO Kevin Mather, in his now-infamous speech to the Bellevue Breakfast Rotary Club, acknowledged Kelenic will likely be called up as soon as the Mariners gain an extra year of team control. Kelenic suffered a strained adductor muscle in his left knee in spring training, but once he gets healthy, he has the polished hitting ability and growing power to join Mitch Haniger and Kyle Lewis in a potent Seattle outfield.
10. Nick Madrigal, 2B, White Sox
Age: 24 | Projected Role: 2B
Notable number: 3.3
Madrigal’s swinging strike rate last season, second-lowest of any big league hitter with at least 100 plate appearances.
Madrigal’s debut was interrupted by a separated shoulder that required offseason surgery, but he still managed to hit .340 while showing the elite contact skills that have defined him since his college days at Oregon State. Now healthy, Madrigal will begin the year as Chicago’s starting second baseman and will attempt to become a table-setter at the top of its dangerous lineup.
11. Triston McKenzie, RHP, Indians
Age: 23 | Projected Role: SP
Notable number: Four
The number of pitches McKenzie threw at least 10% of the time last season, giving him a wide and varied starter’s repertoire.
McKenzie missed part of 2018 with forearm soreness and all of 2019 with a back injury, but he returned in 2020 and helped stabilize the Indians’ staff after Mike Clevinger and Zach Plesac were placed on the restricted list for breaking Covid-19 protocols. McKenzie is set to take over a rotation spot in 2021 and has the stuff to become the Indians’ next great pitching success, though he still has to show his rail-thin frame can hold up over a full season.
12. Andrew Vaughn, 1B, White Sox
Age: 22 | Projected Role: DH
Notable number: 55
Professional games Vaughn has played since being drafted third overall in 2019, none above High-A.
Vaughn has yet to take an official Double-A or Triple-A at-bat, but he’s such a dangerous hitter that he’s the favorite to be Chicago's primary DH in 2021. With his ability to work counts, keep his barrel in the zone for a long time and punish baseballs, he projects to hit for average and power and be yet another young force in a loaded White Sox lineup. The only question is whether he will break camp with the team or be called up after they’ve gained another year of control.
13. Spencer Howard, RHP, Phillies
Age: 24 | Projected Role: SP
Notable number: Two
Home runs Howard allowed over his final four starts last season, after allowing four homers in his first two starts.
The Phillies’ top prospect struggled to a 5.92 ERA in six starts last season, but he showed underlying promise with a mid-90s fastball, a swing-and-miss slider and improved control as the year went on. Even if Howard begins the year in the minors, he’ll be back in the Phillies rotation as soon as injuries hit.
14. Cristian Pache, OF, Braves
Age: 22 | Projected Role: CF
Notable number: 12
Home runs Pache hit in 2019 at Double-A and Triple-A, more than his previous three seasons combined (nine).
Widely considered the best defensive center field prospect in the minor leagues, Pache took over as the Braves’ center fielder in the postseason last year and has the speed, instincts and athleticism to be a perennial Gold Glove winner. How much he’ll hit remains an open question, but Pache has progressively increased his power output each season.
15. Ha-Seong Kim, 2B/SS, Padres
Age: 25 | Projected Role: Utility INF
Notable number: 22
Home runs and stolen bases Kim averaged the last six seasons in Korea Baseball Organization.
Kim starred as a perennial 20-20 shortstop in Korea and signed with the Padres for four years and $28 million after being posted in the offseason. He’ll compete with Jake Cronenworth for the Padres’ starting second base job, but even if he doesn’t win it, he has the athleticism to play around the diamond and the offensive potential to force the Padres to get creative to ensure he’s in the lineup.
16. Tarik Skubal, LHP, Tigers
Age: 24 | Projected Role: SP
Notable Number: 11.1
Average inches of horizontal movement on Skubal’s four-seam fastball, sixth-best among qualified lefthanded starters.
Skubal’s rapid ascent culminated in his major league debut last season, where he struck out more than a batter per inning and his 5.63 ERA was inflated by two bad starts. With a 94-98 mph fastball, swing-and-miss changeup and dominant slider, he figures to play a prominent role in the Tigers’ rotation, even if he opens the year in the minors.
17. Ryan Jeffers, C, Twins
Age: 24 | Projected Role: C
Notable number: 51.6
Jeffers’ called-strike percentage in 2020, tied for sixth-best among all major league catchers.
The Twins called up Jeffers when Mitch Garver got hurt, and the rookie played so well he remained the starter even after Garver returned. Jeffers hit .273/.355/.436 in 26 games while displaying impressive framing skills behind the plate, continuing his long track record of production. Jeffers will again contend with Garver for playing time in 2021, but he should still get enough at-bats to continue making an impact.
18. Dane Dunning, RHP, Rangers
Age: 26 | Projected Role: SP
Notable number: 10.1
Dunning’s career strikeout rate per nine innings in the majors and minors despite below-average fastball velocity and a sinker/slider pitch profile.
Dunning impressed in seven starts with the White Sox before being traded to the Rangers for Lance Lynn in the offseason. A groundball pitcher with an effective sinker and slider, Dunning has worked to incorporate a four-seamer and changeup to combat lefthanded hitters. He immediately slots into the Rangers’ rotation and has a chance to thrive pitching most of his games at pitcher-friendly ballparks in Texas, Anaheim, Oakland and Seattle.
19. Bobby Dalbec, 1B, Red Sox
Age: 26 | Projected Role: 1B
Notable number: 62
The percentage of Dalbec’s plate appearances in 2020 that ended in a walk, strikeout or home run.
Dalbec showed off his prodigious power with eight home runs in 23 games in his debut, but that came with a concerning 43% strikeout rate. He has shown the ability to adjust and put a higher rate of balls in play at every level, so the hope is he will do the same in the majors. Dalbec is set to be Boston’s Opening Day starter at first base, though he has the defensive chops for third base if Rafael Devers’ defensive struggles continue.
20. Garrett Crochet, LHP, White Sox
Age: 22 | Projected Role: RP
Notable number: 100.1
Crochet’s average fastball velocity in miles per hour over five relief appearances last season.
The White Sox drafted Crochet 11th overall in June and called him up to the majors in September, where he overwhelmed batters with his electrifying fastball and didn’t allow a run in relief. Crochet has had injury issues in the past and left his lone playoff appearance with forearm tightness, but he appears healthy for 2021 and should be a dynamic bullpen weapon in front of new closer Liam Hendriks.
MLB Prospect Report—April 22, 2021
Mickey Moniak hits his first career home run, Ian Anderson cruises to his first win of the season and more.
Ten Other Rookies To Watch
(Listed in alphabetical order)
Jazz Chisholm, 2B/SS, Marlins
The twitchy Bahamian infielder has impressive power and an exciting, high-energy style of play.
Wander Franco, SS, Rays
Baseball’s No. 1 prospect has yet to play above High-A, but he’s such an elite hitter he could rise quickly in 2021.
Deivi Garcia, RHP, Yankees
Garcia got his first taste of the majors last year and should be a factor for the Yankees again in 2021.
Michael Kopech, RHP, White Sox
Kopech hasn’t pitched since 2018, but his huge stuff gives him a chance to help the White Sox in a variety of roles.
Alejandro Kirk, C, Blue Jays
After pushing Danny Jansen at the end of 2020, Kirk has a chance to become Toronto’s undisputed starting catcher in 2021.
Casey Mize, RHP, Tigers
Rocky debut aside, Mize still has the stuff to be a frontline starter if his health and command hold up.
Luis Patiño, RHP, Rays
Patiño debuted in relief last year but has a chance to be a prominent part of Tampa Bay’s all-hands-on-deck rotation in 2021.
A.J. Puk, LHP, Athletics
Even after all his injuries, Puk still features explosive stuff that will help the A’s in either the bullpen or rotation.
Trevor Rogers, LHP, Marlins
The big lefty’s promise was evident in his debut and he’ll once again be part of an exciting young Marlins' rotation in 2021.
Leody Taveras, OF, Rangers
Taveras’ speed and defense were as good as advertised in his debut. Now he has to prove he can hit.