West Ham United defender Danny Potts spent the night in hospital after his head clash suffered in defeat at Arsenal.

Potts fell to the ground after jumping in a challenge with Gunners defender Bacary Sagna with 18 minutes left of the Barclays Premier League game.

It appeared the defender, on as a substitute, hit his head on the pitch, and was momentarily knocked out.

Potts received lengthy treatment from medical staff, eventually being taken from the field on a stretcher, in a neck brace, receiving gas and covered in an emergency blanket.

Irons boss Sam Allardyce revealed the player will be closely monitored.

He said: "Potts has gone straight to hospital with concussion, he was unable to give the correct answers to the questions (from the doctors). He hit the floor as a dead weight, was out for a few seconds and was not fully conscious when he came off.

"He was able to answer questions, but not in the right way, and they have protected his neck. We were concerned at how long it took.

"But they have to make sure they protect the spine the right way getting them on the stretcher, that is why it took the time it did."