Play Ball!

There's usually a lot of pomp and circumstance at the start of a baseball game, especially a Major League Baseball game. Most of said pomp/circumstance is just that— take, for example, the exchange of lineups. At one point during all of the pre-game foofrah, representatives from both teams will meet with the home plate umpire, usually right at home plate, and exchange lineup cards¹. These cards detail which players are in the starting lineup of each team, along with the positions they will start out in, and where they will slot into the batting order. The Official Lineups are now submitted digitally by each team hours before the first pitch is thrown; this ensures they can be dissemenated to the various online services that report on MLB games. Importantly, the lineup card also lists the rest of the players on the roster as potential substitutes. If a player is not listed on the lineup card, they are not allowed into the game².