Martina landed awkwardly following an aerial challenge with Maxwel Cornet just prior to half-time and was treated on the pitch for several minutes before being carried off on a stretcher and wearing a neck brace.

He had initially been expected to stay in hospital overnight, but Everton later sent out a message on their official Twitter feed which said he had been discharged.

Speaking after the match, caretaker boss David Unsworth said: "He was concussed, by all accounts, and complaining of pains down his neck, so he has gone straight to hospital for X-rays and scans.

"We wish him all the best, we hope he's OK. He is in the best hands now at hospital, and all the right tests and precautions will be made.

"Hopefully it's nothing too serious and he can be back with us as soon as possible."

Everton conceded three times in the final 22 minutes, and had Morgan Schneiderlin sent off as they suffered a fifth straight loss in all competitions.

Three of those have come under Unsworth, who said: "I'm really disappointed with the result. For nearly 70 minutes, we were nearly perfect with our gameplan.

"The effort was there, the commitment was there, in periods we showed some nice touches and created a couple of opportunities against a very good team.

"But we just can't cave in the way we did when we concede a goal, and that is something we need to rectify very quickly, going into Sunday's game."

Everton face Watford at Goodison Park in the Premier League on Sunday, and Unsworth said he would be "trying to pick a team to try to go and win a massive game on Sunday, a cup final for me."

He added: "We need to start winning games, particularly on Sunday, where I think it's a huge game for me and a huge game for the club, and I've left the players in no uncertain terms that it is a huge game for them as well.

"I'm sure they will respond and the Goodison faithful will get behind us all, because we need them. We need three points."