West Ham United defender Daniel Potts will remain in hospital on Thursday after suffering a head injury on Wednesday night.
Potts, 18, sustained concussion after he was knocked out following a heavy collision with Bacary Sagna in the second half of West Ham's 5-1 loss to Arsenal.
The defender, who has made two Premier League appearances this season, will remain in hospital for further tests
A statement on the club's official Twitter feed read: "West Ham United can confirm that Dan Potts will undergo scans and further assessment in hospital on Thursday.
"On behalf of Dan, the club would like to thank fans for all their messages of support for the defender and join them in wishing him well."
Speaking after the match, manager Sam Allardyce 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."