be/go down to ten men idiom
（足球比赛中）一名球员被罚下场，只剩下十名球员
in football, to have a player on your team sent off (= ordered to leave the playing area because they have done something wrong), leaving ten players to play the rest of the game
By half time, the team was down to ten men after the captain was sent off. 到下半场时，在队长被罚下场后，全队不得不以十人应战。