|Backyard Baseball makes its PlayStation 2 debut in a game combining playground atmosphere along with real players and teams. The twist is that the ten "real" players in the game appear as children along with the rest of the sandlot lineup. Featured pros include Sammy Sosa, Randy Johnson, Mike Piazza, Shawn Green, Barry Bonds, Ichiro Suzuki, Pedro Martinez, Alex Rodriguez, Derek Jeter, and Jim Thome. They'll compete along with 30 Backyard Kids, a combination of girls and boys, in the following three modes of play: Pickup Game, Season Play, and Home Run Derby.
Pickup Game has players selecting two teams from a pool of 40, adjusting options such as difficulty level, game length, and whether or not to include power-ups, as well as the home field. A total of nine fields are available, from a beach to a swampland to a junkyard. No matter which team is selected, players must pick and choose members in true playground fashion. Each character is rated from one to ten in the following areas: power, contact, pitching, running, and defense. Players can also create their own child prodigy by selecting hair color, skin, body type, accessories, and more before assigning a certain number of skill points.
Created players are used in Season Mode, where they earn experience points used to increase their attributes. Each Backyard Baseball season spans 18 or 32 games, with individual and team statistics tracked and saved to memory card. Home Run Derby can be played using either a pitch or out limit with up to eight players alternating turns. No matter which mode is selected, players use a cursor-based system for both pitching and hitting. Four available pitch types include a fastball, curve, screwball, and change-up, while hit types consist of power, line drive, grounder, and bunt. Fictional characters Sunny Day and Abner Dubbleplay provide the play-by-play and color commentary, respectively.