Dundee United boss Craig Levein fears Jon Daly suffered a serious knee injury in Saturday's draw with Hibernian.
Daly sustained the injury early on at Tannadice and had to be stretchered off the field.
The Irishman is set to undergo scans on the injury in the next 48 hours, but Levein fears the striker may have damaged his cruciate and medial knee ligaments.
"The doctor thinks Jon has damaged both his cruciate and medial ligaments but we won't know for certain until he's been sent for a scan," Levein told the Daily Record.
"He's a really strong, physical boy and to see him in such pain you know there is something seriously wrong."