Celtic manager Neil Lennon fears Korea Republic defender Cha Du-Ri will be sidelined for several weeks with an ankle injury.
Cha was injured in his first day of training with Celtic after returning from international duty at the AFC Asian Cup and Lennon confirmed after today's 3-1 win at Dundee United that the right-back needs to see a specialist to determine the extent of the problem.
The 30-year-old, who has 58 caps for Korea Republic, has impressed since his pre-season transfer from Freiburg but Lennon could be without him for some time now.
"Cha took a bad one. We are sending him to see another specialist to get another opinion," Lennon said. "We are hoping that he will not require surgery, but even if he doesn't require surgery he will be out for a significant period of time.
"He felt it in the first day of training when he came back. He seemed to jar his tendon. It was pretty innocuous really because he came through the training session OK and only really felt it afterwards."
Cha's injury blow couldn't take the shine off a good day for Lennon as Celtic won at Tannadice to move five points clear at the top of the Scottish Premier League.
Lennon was impressed with the way his players repeatedly opened up the United defence and he said: "At 2-0 you are always concerned that Dundee United could get back in the game, and they did.
"But there was a real belief about the team that they could have got another one, which they did, and really we should have picked Dundee United off a lot better on the counter attack when they were throwing bodies forward.
"We got a bit of luck with the first two goals but I thought we earned it. We missed easier chances and should have been more clinical at times, but the fact we created quality chances really pleased me. I'm really pleased with the threat we have and we defended solidly too."