A game cannot begin if each team has less than eight (8) participants. A game may not be resumed if each team has less than nine (9) players. If each side has less than eight (8) players, the game cannot be resumed. When a player is injured and cannot continue, a substitute can replace him/her only if he/she is on the roster of a different team or if his/her team has its maximum number of players used. In either case, the substitute must come from outside the team lineup. Little League rules are complex, so it's best to check with your local league before making plans. However, most leagues will allow you to add players to existing teams after they have started playing if necessary. If you identify any possible problems with the rules before you start, such as two teams with eight players on them, you can address those issues then. The last thing you want to do is start a game that isn't legal! Little League has some great videos available on their website for anyone who wants to learn more about the game. Be sure to check them out before you start playings games!