MLB The Show 21 is the 16th entry in the officially licensed baseball series. The game features all 30 major league teams and their full roster of players. Also included are each team's minor league affiliate teams at the AA and AAA level. There are a number of playstyle and difficulty options that allow players to customize the experience, ranging from pick up and play to competitive and simulation modes. The game also offers a dynamic difficulty setting that tailors the game's challenge level based on the player's performance in each phase of the game. Pitching, batting, and fielding each have independent difficulty settings, and players can choose from multiple control scheme options.
This version of the show includes the classic exhibition, franchise, and Road to the Show career mode in previous entries while also adding an overhauled version of Diamond Dynasty mode. Players earn experience points and in-game currency in every mode, allowing them to purchase card packs to improve their Diamond Dynasty team or their Road to the Show player's stats and abilities. New to the game is the ballpark creator mode, allowing players to design and create their own stadiums from scratch as well as edit the scenery, ballpark dimensions, wall height, and foul territory in existing parks. Players can also download other user created parks using the in-game community system.
Matt Vasgersian, Mark DeRosa, Dan Plesac, and Heidi Watney all reprise their roles as in-game commentators and analysts. The game offers multiple presentation modes ranging from an "on the field" experience to a TV broadcast mode. For the first time in the series' history, the game was released on Xbox consoles, and there is cross platform compatibility between the PlayStation 4 and PlayStation 5 versions.