No extra innings unless during playoffs. An official game is four and a half innings provided that the home team is ahead, otherwise five innings. If a ninth player arrives after the beginning of the game, he or she can be inserted in the ninth spot. However, the player must enter the game no later than the beginning of the fifth inning or the team will finish with eight players. If a team can't field at least eight players or a coach isn't present by fifteen minutes after the scheduled start of the game, it is a forfeit.
Tenth player is optional.
Tenth player must be an outfielder in some capacity. That position must be played the entire game. Umpires will adhere to the mandatory slide rule on close plays. Umpire will go over this during ground rules explanations prior to the game. Umpire will also adhere to malicious intent rule, meaning that if a player, for example, is perceived to make an attempt to come into physical contact with the second baseman during a double play, both the runner and the batter will be called out.