West Ham manager David Moyes has praised his club's medical team for how they handled Issa Diop following his clash of heads with Manchester United forward Anthony Martial.
Diop has since been checked again and found not to have had concussion.
"My medical team took the right action," said Moyes.
"It was a tough one because we were short of players. But Issa had a bump on his head, which was a bit of an egg so we took him off. Interestingly, Anthony Martial played on.
"We felt we did the things which were the best for our player.