Crewe defender Adam Dugdale will be sent for a brain scan after being knocked unconscious against Shrewsbury on Saturday.
The 26-year-old has been ruled out of the Boxing Day clash at Wolves and although he returned to Alex's training ground on Monday, boss Steve Davis has been advised to keep him away from contact training for the next five days.
Dugdale lay motionless on the Gresty Road turf for five minutes when he sustained the head injury against the Shrews early on in the game but he returned from hospital later that day.
On his Twitter account that night, Dugdale said: "Home from the hospital. I had server (sic) concussion &can't remember much about it. Scary experience,feeling better,thanks for all ur kind msgs!"
However, Davis is keen to adopt caution and will heed doctor's advice with regards to keeping him out of action for the foreseeable future.
Speaking to the club's official website, the Crewe boss said: "On medical advice Adam won't play at Wolves. He will be out for the recommended five days and there won't be any contact or heading the ball.
"Adam will visit the doctor and have a brain scan just make sure everything is okay. I'm sure he will he be."