Officials ruled that Gunners goalkeeper David Raya was fouled at a corner by Pablo Felipe just before Callum Wilson scored to bring the Hammers level.

The Nigerian was placed in an induced coma to aid his recovery from urgent abdominal surgery.

Any player on the pitch could be shown a blue card, PA understands, but not substitutes or team coaches.

The International Football Association Board (IFAB) has supported the move following a successful implementation in the grassroots game.