Each team has a retro uniform that can be unlocked by performing various tasks in season mode.

Uniform	How to unlock
Arizona Diamondbacks Retro Uniform	Hit both a game-tying home run and a walk-off home run in the same game as the Diamondbacks.
Atlanta Braves Retro Uniform	Hit 2 home runs in an inning as the Braves.
Baltimore Orioles Retro Uniform	Hit 3 home runs in 3 consecutive games with the same player as the Orioles.
Boston Red Sox Retro Uniform	Steal 4 bases with the same player in a single game as the Red Sox.
Chicago Cubs Retro Uniform	Get 12 RBIs from pitchers over 30 games as the Cubs.
Chicago White Sox Retro Uniform	Get 5 hits from the same player in a single game as the White Sox.
Cincinnati Reds Retro Uniform	Hit 4 home runs in a single game as the Reds.
Cleveland Indians	Score first in 12 straight games as the Indians.
Colorado Rockies Retro Uniform	Get a hit with the same player in 20 straight games as the Rockies.
Detroit Tigers Retro Uniform	Get two home runs in a game with the same player 3 times as the Tigers.
Houston Astros Retro Uniform	Hit a single, double, triple, and home run in the same game as the Astros.
Kansas City Royals	Win after trailing by 4 runs as the Royals.
Los Angeles (Brooklyn) Dodgers Retro Uniform	Hit a grand slam with a pinch hitter as the Dodgers.
Los Angeles (California) Angels of Anaheim Retro Uniform	Get 3 extra-base hits with the same player in a single game as the Angels.
Miami (Florida) Marlins Retro Uniform	Have the starting pitcher record 9 strikeouts while allowing no runs over 7 innings as the Marlins.
Milwaukee Brewers Retro Uniform	Win with a walk-off home run after trailing by 4 runs as the Brewers.
Minnesota Twins Retro Uniform	Get 2 consecutive shutouts as the Twins.
New York Mets Retro Uniform	Allow 10 hits or fewer and get 25 strikeouts over 3 wins as the Mets.
New York Yankees Retro Uniform	Get 4 RBIs in 2 consecutive games with the same player as the Yankees.
Oakland Athletics Retro Uniform	Get 9 saves with a reliever over 10 consecutive save opportunities as the Athletics.
Philadelphia Phillies Retro Uniform	Score 4 runs in the 10th inning or later as the Phillies.
Pittsburgh Pirates Retro Uniform	Get 15 RBIs over 10 consecutive games with the same player as the Pirates.
San Diego Padres Retro Uniform	Get 7 home runs and 20 RBIs over 25 consecutive games with the same player as the Padres.
San Francisco Giants Retro Uniform	Get a hit from every player in the starting lineup, including the pitcher, as the Giants.
Seattle Mariners Retro Uniform	Score 4 runs in the 10th inning or later as the Mariners.
St. Louis Cardinals Retro Uniform	Pitch a shutout with 12 strikeouts as the Cardinals.
Tampa Bay (Devil) Rays Retro Uniform	Get 8 strikeouts over 5 consecutive innings as the Rays.
Texas Rangers Retro Uniform	Get 2 consecutive shutouts as the Rangers.
Toronto Blue Jays Retro Uniform	Get 8 strikeouts over 5 consecutive innings as the Blue Jays.
Washington Nationals (Montreal Expos) Retro Uniform	Get 30 hits over 100 consecutive at-bats as the Nationals.