While some players find success at a young age, others take years to reach their potential, grinding away until something finally clicks. Take White Sox designated hitter Yermín Mercedes, for example.
After playing eight Minor League seasons with three organizations (Nationals, Orioles, White Sox) and logging only one big league plate appearance prior to 2021, Mercedes has been one of MLB's hottest hitters early this season. He leads the Majors in batting average (.432) and is tied for the lead in hits (33).
What remains to be seen is whether Mercedes can keep it up, not only for the rest of this season but also for multiple years, like the players below.
Each of these players had fewer than 10.0 career wins above replacement (per Baseball-Reference) through his age-26 season, and none reached 4.0 bWAR in any single year before age 27. All eventually went on to become stars, earning themselves a place on our All-Late-Bloomer Team. (For the purposes of this story, players whose Major League debuts were delayed by an off-the-field circumstance, such as segregation or military service, weren’t considered.)
Catcher: Jorge Posada
A member of the Yankees’ “Core Four” with Derek Jeter, Mariano Rivera and Andy Pettitte, Posada won four World Series titles with New York and finished his career with 275 homers, 1,065 RBIs and a 121 OPS+. However, Posada didn’t break out until his age-28 season in 2000, when he earned the first of four consecutive All-Star selections and won his first of four straight Silver Slugger Awards. Before that, Posada was a league-average bat, posting a 100 OPS+ over his first 292 games.
First base: Edwin Encarnación
Encarnación was a solid hitter over his first seven seasons (104 OPS+), but nothing close to what he became in 2012, when he recorded 42 homers, 110 RBIs and a 153 OPS+ at age 29 for the Blue Jays. It kicked off a stretch of eight consecutive seasons with at least 32 home runs for Encarnación.
Second base: Jeff Kent
The all-time leader in home runs as a second baseman with 351, Kent showed flashes of that power over his first five seasons, hitting 20-plus homers twice in that span. However, it wasn’t until Kent was traded to the Giants that he became a multi-time All-Star and perennial MVP candidate. Kent finished his career with 55.4 bWAR, 45.1 of which came after he turned 29. From 1997 through 2005, Kent averaged 28 homers and 110 RBIs per season while recording a 132 OPS+. He won the National League MVP Award in 2000, producing 33 homers, 125 RBIs, a 162 OPS+ and 7.2 bWAR.
Third base: Josh Donaldson
Donaldson was originally a catcher when the Cubs picked him 48th overall in the 2007 MLB Draft, and he took a while to find a permanent position after being traded to the A’s in the Rich Harden deal. But at age 27 in 2013, the Auburn University product took over as Oakland’s starting third baseman and finished fourth in the American League MVP Award race. Traded to the Blue Jays in November of '14, Donaldson hit .297/.371/.568 (151 OPS+) with 41 homers and 123 RBIs the following season, winning AL MVP honors over Mike Trout. From 2013-20, Donaldson had the fifth-most bWAR (39.9) among position players, trailing only Trout, Mookie Betts, Paul Goldschmidt and Nolan Arenado.
Shortstop: Maury Wills
Wills signed with the Dodgers as a teenager prior to the 1951 season, but he didn’t make his MLB debut until he was 26 years old in ’59. Although the speedster struggled in his rookie year, he was an MVP by his fourth season, recording 208 hits, 104 steals and 130 runs in 1962. Wills earned All-Star selections in 1961, ’62, ’63, ’65 and ’66 and was the first-ever All-Star Game MVP in ’62. He finished his career with 2,134 hits and ranks 20th all time with 586 steals.
Left field: Brian Giles
Giles spent the majority of his career playing for small-market teams in Pittsburgh and San Diego, so you might have forgotten how good he was at his peak. The outfielder recorded an OPS of 1.000 or better over 600-plus plate appearances in three seasons, the same number as Hall of Famers Chipper Jones, Ken Griffey Jr., Frank Robinson and Hank Aaron. Giles broke in with the Indians and was a part-time player through his age-27 season in 1998. After being traded to the Pirates for Ricardo Rincon, Giles posted a 1.030 OPS (160 OPS+) over his first four seasons with the Bucs, averaging 37 homers and 6.0 bWAR per year in that span. While his power dropped off once he became a Padre, he still recorded 19.3 bWAR with San Diego from 2003-08.
Center field: Earl Averill
Of all the position players in the Hall of Fame, Jackie Robinson is the only one who debuted at an older age than Averill. Averill first appeared in the big leagues a little over a month before his 27th birthday in 1929 and was terrific from the get-go, hitting .332/.398/.538 with 18 homers as a rookie. Averill was selected as a reserve for the first All-Star Game in 1933 -- one of six All-Star selections for the Washington native. He averaged 5.1 bWAR per season from '29-38, posting a 137 OPS+ in that span.
Right field: José Bautista
After producing 59 homers, a 91 OPS+ and 0.0 bWAR in his first six seasons, Bautista tinkered with his swing and became one of MLB’s most feared sluggers out of nowhere. Playing for the Blue Jays (his fifth big league team) in 2010, Bautista led all players with 54 home runs and posted a 164 OPS+ with 7.0 bWAR at age 29. He was even better the following season, recording a 182 OPS+ with 8.3 bWAR while topping MLB's home run leaderboard again (43 homers). Bautista also reached the 40-homer mark in '15 -- helping Toronto snap a 21-year postseason drought in the process -- and went on to hit one of the most iconic playoff blasts in recent memory, crushing a go-ahead, three-run homer that he punctuated with an epic bat flip in Game 5 of the ALDS against the Rangers. From '10-15, Bautista averaged 38 homers and 5.9 bWAR per season with a collective 156 OPS+.
Designated hitter: David Ortiz
Ortiz was an above-average bat during his time with the Twins (108 OPS+), but it wasn’t until he arrived in Boston that he became a legend. After being released by Minnesota in December 2002, Ortiz signed with the Red Sox and finished fifth in the ’03 AL MVP race at age 27. The following year, Ortiz etched his name in Boston sports lore, leading the Red Sox back from a 3-0 ALCS deficit against the rival Yankees and helping the club win its first World Series title since 1918. Ortiz brought two more championships to Boston and won the 2013 World Series MVP after slashing .688/.760/1.188 in six Fall Classic games as a 37-year-old. He played his final season at age 40 in '16, hitting 38 homers and leading MLB in OPS (1.021). All told, Ortiz slugged 483 home runs during his Red Sox career, which lasted 14 seasons. Hall of Famer Edgar Martinez would also be a fine choice for this spot, as he posted 67.7 bWAR with a 149 OPS+ from age 27 onward, but his counting stats and postseason resume don't measure up to Ortiz's.
Utility: Ben Zobrist
Arguably the best utility man in history, Zobrist saw limited action over his first three seasons before breaking out with 8.6 bWAR for the Rays in 2009. From age 28-33, Zobrist averaged 6.0 bWAR per season and made 100-plus appearances at three positions (2B, SS, RF). As a 35-year-old in 2016, he made his third and final All-Star team and was named World Series MVP after helping the Cubs end their 108-year title drought.
Pinch-hitter: Nelson Cruz
We wanted Cruz on this team, but with right field and DH covered, he’ll have to come off the bench as a pinch-hitter. Initially signed by the Mets as an amateur free agent out of the Dominican Republic in 1998, Cruz was traded three times before finding a home with the Rangers. Cruz first became a big league regular in 2009, producing 33 homers with a 117 OPS+ at age 28. After recording 135 home runs in the regular season and another 14 in the playoffs for the Rangers from 2009-13, Cruz signed a one-year deal with the Orioles and socked 40 dingers for the first time in his career. He moved on to the Mariners and crushed 37 or more homers in every season from 2015-18, then hit 57 round-trippers in 173 games for the Twins across '19-20. He’s one of nine players to reach the 40-homer mark at least four times after his 30th birthday.
Starting pitcher: Randy Johnson
For a while, it seemed as though Johnson’s poor control would be the story of the 6-foot-10 left-hander’s career. Over his first five seasons, Johnson walked 14.5% of the batters he faced and posted a 101 ERA+ in 818 innings. But at age 29 in 1993, the Big Unit shaved his walk rate to 9.5%, struck out 308 batters in 255 1/3 frames and went 19-8 with a 3.24 ERA (135 ERA+). Two years later, Johnson won his first Cy Young Award. The southpaw collected four more after signing with the D-backs, and he was 38 years old when he earned World Series co-MVP honors alongside Curt Schilling in 2001. Johnson joined the 300-win club with the Giants in '09, finished second all time in strikeouts (4,875) and made the Hall of Fame in 2015.
Starting pitcher: Phil Niekro
Widely considered to be the greatest knuckleballer of all time, Niekro pitched for 24 seasons -- 21 with the Braves -- and is a member of the 300-win and 3,000-strikeout clubs. The right-hander collected all but six of his wins after his 28th birthday in 1967, a year he led MLB with a 1.87 ERA (179 ERA+) over 207 innings. Niekro ranked sixth or better in the Cy Young voting at age 30 (second), 35 (third), 39 (sixth), 40 (sixth) and 43 (fifth), and he had seven 200-inning campaigns after turning 40. Jamie Moyer, Nolan Ryan and Jack Quinn are tied for second with four apiece. Niekro was inducted into the Hall of Fame in 1997.
Starting pitcher: Max Scherzer
It’s hard to remember a time when Scherzer wasn’t one of the best pitchers in baseball, but he didn’t arrive at that point immediately. The right-hander posted a 3.92 ERA (109 ERA+) over his first four seasons, and he had a 4.72 ERA through 22 starts in his fifth. But Scherzer wrapped up the year with a 1.65 ERA over his final 10 starts, then won the AL Cy Young Award in 2013 at age 28. Scherzer signed with the Nationals after the '14 campaign and won two more Cy Young Awards and a World Series title in D.C., recording a collective 2.80 ERA (152 ERA+) with an 11.8 K/9 rate in his first six years with the club.
Starting pitcher: Dazzy Vance
Vance is a unique case in that he debuted in 1915, didn’t pitch in the big leagues again until ’18, then went another four years before getting back to MLB in ’22. By that time, he was 31 years old and the Live Ball Era was in full swing. Vance went on to lead the NL in strikeouts in seven straight seasons, winning the league MVP Award in 1924 after going 28-6 with a 2.16 ERA (174 ERA+) and 262 K’s over 308 1/3 innings for the Brooklyn Dodgers. The righty pitched into his mid-40s, retired with a lifetime 125 ERA+ and 60.1 bWAR, and was enshrined in Cooperstown in 1955.
Starting pitcher: Jacob deGrom
Selected by the Mets in the ninth round of the 2010 MLB Draft out of Stetson University, deGrom underwent Tommy John surgery after just six Minor League games and took four years to reach the Majors, finally debuting a month before his 26th birthday in 2014. After posting a 2.98 ERA over his first four seasons, deGrom has taken his game to an even higher level since 2018, winning multiple Cy Young Awards and cementing himself as one of the greatest pitchers of his generation.
Setup: Hoyt Wilhelm
Wilhelm fought for the United States Army in World War II, but his delayed MLB debut can’t be pinned entirely on his military service, as he spent six seasons in the Minors after the war ended. Wilhelm finally got the call to the Majors at age 29 in 1952 and went on to win the NL ERA title with a 2.43 mark over 159 1/3 innings -- all in relief. Wilhelm pitched for 21 years and posted a lifetime 147 ERA+ over 1,070 appearances, and he was inducted into the Hall of Fame in 1985, the first reliever to receive the honor.
Closer: Joe Nathan
After a rough start to his career, Nathan became one of the Giants’ best relievers in 2003, his age-28 campaign, recording a 2.96 ERA over 79 innings. Traded to the Twins with Francisco Liriano and Boof Bonser for A.J. Pierzynski, Nathan took over as Minnesota’s closer and finished 2004 with a 1.62 ERA, 89 K’s and 44 saves in 72 1/3 innings, placing fourth in the AL Cy Young Award balloting. The righty ended up recording a lifetime 151 ERA+ with 377 saves -- 376 of them after his 29th birthday.