Derby County captain Chris Baird is expected to miss the next two games after suffering a head injury in the win over Preston North End on Saturday.
The Northern Ireland international, 33, was briefly knocked unconscious and needed 11 minutes of treatment after a clash of heads before being taken off.
He was given the all-clear after scans, but must follow the correct procedures for head injuries before returning.
Baird could miss Tuesday's match at Reading and the game with Burnley.
Manager Paul Clement said: "Every day the doctor is checking on his symptoms. Every day he has to show he is symptom free, so it is a day-by-day process.
"We are hoping it is seven days, but it could be a little longer."