Virgin Interactive's first PlayStation baseball game introduces a few new twists to the hitting and pitching mechanics found in previous sports games. Pitching in Grand Slam relies on timing button presses within a circular meter to set both velocity and accuracy. The default hitting interface has players aiming a rectangular cursor over the plate and then holding down a power button to determine the swing's strength. Fielding offers a choice of perspectives: a view from behind the athlete or one looking toward the stadium.
Grand Slam features an MLBPA license for 800 authentic players with individual ratings based on the 1996 season and team rosters taken from 1997's Opening Day. While stadiums have been modeled after big-league ballparks, the lack of a Major League Baseball license means teams are listed by city instead of name. Players can take their hacks in one of four game modes: season (adjustable to 13, 52, or 162 games), "tater" (the equivalent of a home run derby), exhibition, and practice. A memory card is required to save season progress and statistics.