Paul Connolly, the Crawley Town defender, appeared to swing an arm at a Brentford fan after he had the ball powerfully thrown at him during the Bees' 1-0 League One win.
Connolly, 30, confronted the man at Griffin Park after he went to retrieve the ball for a throw-in.
Connolly is restrained after his confrontation with the Brentford fan
Brentford kept up the pressure on Sky Bet League One Leaders Wolves as they beat Crawley 1-0 on Tuesday night.
Jonathan Douglas headed the only goal of the game in the 58th minute as the Bees moved just three points behind Wolves and nine clear of third-placed Rotherham after they slipped up at Sheffield United.