Hearts forward Steven Naismith is a doubt for the Scottish Cup quarter-final with Partick Thistle on Monday with a knee problem.
The Scottish International was forced off at half-time during Hearts' 2-1 defeat at home to Celtic on Wednesday night.
Hearts manager Craig Levein says Naismith has been struggling with the problem since having surgery in October.
He said: "He's had an operation obviously, a little bit of cartilage shaved off. That was the same knee and it was irritating him, so I don't know."
Despite injury problems and the last-gasp defeat to Celtic, the Hearts boss is encouraged going into their last eight tie at Firhill.
He added: "I think there was enough in our performance to see that we can really compete with everybody again. We competed with the team that is recognised as the best in the league.
"There were some good performances by players who have had injury problems and have struggled to get right back to their best, which gives me a fair bit of pleasure, because I feel that's them back to where they were previously."