10 - 9 fielders and the batter.
0. The middle of the inning is a part of the inning. There technically doesn't have to be any players on the field at that point.
There must be a minimum and maximum of 9 players on the field for the defensive team which will include their current Pitcher on the mound however the offensive team can have a minimum of 1 player on the field and a maximum of 4 players on the field.
There are 6 outs in each inning.
Each team has an active roster of 25 players.
Ten: nine position players on defense (Catcher, pitcher, first base, second base, shortstop, third base and three outfielders) and a batter at the plate on offense.
In MLB the minimum and maximum number of players on the field is 9. In each half inning their are 3 outs, so there are 6 outs per inning, three per team.
25 players are active during the season.
Major League baseball teams are allowed a roster of 40 players with 25 allowed to be active during the regular season until September when the active roster can be expanded up to the 40 player limit. Only nine players may be in the lineup and any one time during a game.
1. Players are paid 1/162 of their salary for each game they are active. As long as they are on the major league roster during the season, they will earn at least the minimum
During the regular season, there can only be 12 active players. so 36 players. However, there can be more, just not all of them will be active.