Exact how many player in baseball game?

Answer 1

On defense, nine players will be on the field at any one time including the pitcher and the catcher who is the only player to lineup outside fair territory.

On offense, there can be only four players on the field, one at each base and one in the batter's box. There is one other offensive player, the next batter due up, who may be in the "on-deck" circle. In most Baseball leagues, the offensive team must have a player in the "on-deck" circle.