As the manager of your own big league club, you choose your starting lineups from rosters of real players. You decide when to use a pinch hitter, attempt a steal, take the extra base on a hit or fly ball, bring in a relief pitcher, pitch around a hitter, and more. After the game, you can print or save to file a boxscore or play-by-play scoresheet of the game.
Almost everything that happens on the field in big-league baseball can happen in Diamond Mind Baseball, including rundowns, pickoffs, outfielders missing the cutoff man, arguments with umpires, ejections, dropped third strikes, brawls, and pitchers leaving games when their arms stiffen during a long rain delay.