Everton midfielder Gareth Barry says Chelsea striker Diego Costa did not bite him when they clashed during Saturday's FA Cup quarter-final.
Costa was shown a second yellow card for his part in the incident, in the 84th minute of Chelsea's 2-0 defeat at Goodison Park, but denied biting Barry.
The Toffees player, who was later sent off, has backed Costa's claim.
The Football Association is awaiting referee Michael Oliver's report before deciding if more action is necessary.
Costa responded to a tackle from Barry by confronting the England international, moving his head towards him and in the direction of his neck.
Blues manager Guus Hiddink said the 27-year-old striker had been "chased a bit in the game" and was provoked by Everton players.
Barry was sent off three minutes after Costa when he was shown a second yellow card for a foul on Cesc Fabregas.
Everton manager Roberto Martinez said the 35-year-old had not complained after the match about his clash with Costa.
Former referee Howard Webb told BBC Radio 5 live: "I'll be amazed if Costa is not punished for his reaction after the second yellow card.
"He fails to leave the field of play, he is aggressive again to Michael Oliver and referees are always told to report that situation. That can lead to another match ban."
But on the suggestion Costa had bitten Barry, he added: "From what I've seen of the footage, it is not sufficient to support a charge for violent conduct retrospectively."
'Let's not get too carried away'
Burnley midfielder Joey Barton has been involved in several controversial incidents during his career and is wary of making too much of Costa's actions.
"It's difficult to get too self-righteous when you're in my position, but what we have to remember is nobody has died," he told BBC Radio 5 live's Sportsweek's programme.
"It's a game of football. You have had two grown men basically square up, no punches have been thrown, nothing serious has happened, both have gone home to their families, one team has lost, one team has won.
"We have to be careful not to get too carried away. We have to remember what makes football football.
"It's that kind of thing, it's goals, it's playing on the edge, it's high intensity, it's high passion. That's why we do what we do, that's why we love watching football."