Don't know what the baseball rulebook says but it is very clear in football that it would be the jv game. Virtually impossible to ever lose the varsity football contest due to a player playing too many quarters. Seems like you should lose the game that the violation occurred, but that may be a bit punitive if it was only a few pitches. Brings to mind the George Brett illegal pine tar game.
Quarters Q. 54-2 When a player participates in more than the allowed number of football quarters on successive days or during a week, what action is required?
A. A violation of the maximum contest rule requires that the School to forfeit the game in which the player exceeded the limit, charge the player with each quarter of participation, and send a written report to the Commissione