In baseball, it is traditional to give aging veteran players the day off when the schedule calls for playing an afternoon game the day after an evening game.
The result is that afternoon games, the ones with the most young children in attendance, often feature each team's "B roster" of scrubs.
As someone with a ticket to this afternoon's Nats-Giants game, I hope Barry Bonds does not have the day off.
Besides, older players probably do better during the day than at night. (I'm sure someone keeps a stat for this. Josh, I'm looking in your direction.) Thus, why not let players rest during the night game and let them play the following afternoon?