In 1929, uniform numbers appeared on the back of baseball jerseys for the first time, thanks to the Indians and the Yankees.  By 1937, numbers finally appeared across all uniforms, both home and away, across both major leagues.  Since that time, 81 distinct numbers have been worn by members of the White Sox, while the Cubs boast 76.

Today, we continue our look at those players, picking our favorite, if not the best, player to wear each uniform number for both Chicago teams with #21.  69 different players have donned #21 while playing in Chicago, 26 for the White Sox and 43 for the Cubs.

Near the end of the spring training in 1992, Sammy Sosa, along with Ken Patterson, was acquired from the White Sox for a fading George Bell.  Wearing #21, Sosa blossomed with the Cubs, going from 8 home runs and 25 RBIs in his first season to 33 home runs and 93 RBIs in his second, becoming the first 30-30 player in Cubs history.  Sosa continued to hit for power and speed in 1994, but he also upped his batting average to .300 for the first time.  Sosa was named to his first All-Star team in 1995, on his way to 36 home runs and 119 RBIs.  In 1996, Sosa continued his success, hitting .273 with 40 home runs and 100 RBIs.  1997, however, saw a decline in Sosa, who batted just .251 and posted a paltry .300 on-base percentage while leading the league with 174 strikeouts, despite hitting 36 home runs and driving in 119 runs.

A bulked-up Sammy Sosa arrived in camp in 1998, looking to turn things around, and turn them around he did.  While the surprising Cubs were in contention for the first time in nearly a decade, Sosa put on a home run barrage of historic proportions.  In the month of June, Sosa launched 20 home runs, drove in 47, and slugged .842 while pulling himself into the home run chase with Mark McGwire.  Sosa hit his 62nd home run on September 13, passing Roger Maris, and finished the season with 66, 4 behind McGwire’s then-record 70.  Sosa replicated that performance in 1999, hitting 63 home runs, again trailing McGwire, who hit 65.  Sosa finally led the league in home runs in 2000, though with “only” 50.  He managed another season for the ages in 2001, as he hit 64 home runs, becoming the first player to hit 60 or more home runs three times, and setting career highs in runs scored, RBIs, walks, OBP, slugging percentage, and batting average.  He notched his second career home run crown in 2002, adding 49 to his ledger.

Things started to turn for Sosa in 2003, despite the Cubs driving towards their first division title since 1989.  He went on the disabled list for the first time since 1996 in May and, when he returned, he was ejected, and ultimately suspended, for using a corked bat in the June 3 game against the Devil Rays.  He finished the season with 40 home runs, his lowest total since 1997, as the Cubs famously blew a 3-1 lead in the NLCS despite being 5 outs away from the pennant in Game 6.  The following May, he landed on the disabled list again following a violent sneeze at PETCO Park.  After returning from the DL, Sosa struck out 98 times the rest of the way, while hitting .238 and posting an OPS of .749.  For the entire year, Sosa hit .253, his worst average since 1997, with only 35 home runs and 80 RBIs, his lowest total since 1994.  When the Cubs fell out of contention for the NL Central title after losing 7 of their final 9 games, Sosa was given the day off for the final game of the season.  Unfortunately, he was spotted leaving Wrigley Field before the game even started while his teammates took out their frustrations with their “leader” my smashing his boombox with their bats.  That January, with the declined performance and the growing suspicion of PED use on their minds along with the end of the 2004 season, the Cubs decided to move on, trading Sosa to the Orioles for Jerry Hairston Jr. and Mike Fontenot.

On the South Side, Todd Frazier wore #21 after being acquired from the Reds in a three-team deal prior to the 2016 season.  On July 11, Frazier placed second in the Home Run Derby, losing to Giancarlo Stanton in the final round.  Frazier finished the year with career highs in home runs, runs batted in and walks despite hitting a career low .225 batting average in 158 games.  With the White Sox throwing in the towel and entering a full-fledged rebuild in 2017, Frazier was traded to the Yankees at the deadline.