Celtic boss Gordon Strachan is concerned about Stephen McManus' ankle injury, admitting his captain is 'too brave for his own good'.
McManus was replaced at half-time during Saturday's 1-1 draw at Hearts, with Strachan not willing to risk the defender's fitness further.
The Scotland international is being assessed by club doctors, with Strachan having to stand firm over his skipper.
"He is too brave for his own good," said Strachan.
"A 90 or 80 per cent fit Mick is good, but 50 per cent or less is not really good enough.
"I felt sorry for him, but I do feel he has to say enough is enough. The pain is too much.
"We kept asking him and he kept saying he was fine. Then I have to make the decision for his own good and ours.
"It's his ankle. He pushed himself to play for Scotland and just does not want to lose that place.
"It's the same for Celtic, but we had to be strong with him at half-time.
"The docs will have to take it from here."