Well, you don't need any players at all in a line. The only position with a definite amount of players is the goalkeeper, with 1 player. The most common amount for a formation is 4-4-2. Four Defenders, four midfeild and 2 strikers. Any amount ca play on each line(appart from goalkeeper who need a definite one) as long as the total adds up to the whole 11 players
Eleven in each team.
When a game of football/soccer starts, there are 11 players on each team.
There are 11 players on each side.
11 players play for each team in a soccer match (including the goalkeeper.)
11 on each team.
There are 11 players in a football team for each side on the pitch at any one time.