Dan Potts has returned home from hospital after suffering a suspected concussion during West Ham's 5-1 defeat to Arsenal on Wednesday.
The defender, 18, had remained in for observation after a clash of heads with Bacary Sagna before landing awkwardly. He was treated on the pitch for around 10 minutes before leaving in a neck brace and receiving gas.
"I am looking to be feeling better over the next few days," Potts said. "A big thank you to everyone for their support and messages."
A statement on the club's official website added: "There will be a period of rest for Potts before he is allowed to start light work back in the gym.
"The club would also like to thank the London Ambulance Service, the on-site pitch rescue team and everyone at Arsenal who helped in making sure Potts was taken to hospital as quickly as possible.
"The 18-year-old spent Wednesday evening in hospital and underwent further scans and tests which came back positively on Thursday."
West Ham boss Sam Allardyce expressed concern over Potts' injury after the game, and confirmed he will not make a return to action for two weeks.
He said: "The clash of heads initially knocked him out and he hit the floor as a dead weight and I think that is what the problem was.
"He hadn't spoken when he came off the field. He spoke about some things that they asked him on the pitch but they were not the correct answers so that is how we knew he was concussed. He was communicating but was obviously confused.
"Hopefully it is just concussion. Because he lost consciousness it is a minimum of two weeks, I think, before he can play again."
Potts, a product of West Ham's youth system, made his debut in December 2011 during a 1-0 win against Barnsley and is the son of former Hammers defender Steve who represented the club for over 15 years.