David Luiz struck Arsenal team-mate Dani Ceballos in the face during a sensational training ground bust-up over the international break.
The pair had to be separated by manager Mikel Arteta after a challenge by Ceballos sparked a scrap.
The fight occurred during a practice match last Friday, when many of the Arsenal squad were away with their national sides.
The pair were sent home from training last Friday and have since apologised to each other
The match involved senior players not away on international duty and players from the club’s academy.