West Ham United defender Dan Potts was kept in hospital overnight after being knocked unconcious in the 5-1 defeat to Arsenal.
The 18-year-old suffered concussion after a clash of heads during the second half last night and was treated on the pitch for ten minutes before being taken to hospital. Potts will undergo scans and further assessment today.
West Ham boss Sam Allardyce told the club website: "Dan Potts has got a severe concussion. We hope that is all it is.
"He has gone off to hospital and will be under observation at the hospital for however long to get him round and get him home."