Dundee United could be without striker Jon Daly for up to a year after scans revealed knee ligament damage.
The former Hartlepool and Stockport marksman ruptured both his anterior and posterior cruciate ligaments during last weekend's draw with Hibernian.
Daly, for the second time in his career, is now facing surgery and the arduous recuperation process associated with a long-term injury.
The 26-year-old will visit a surgeon to evaluate the best course of action, although Levein does not think the injury will be career threatening.
"Jon has done both cruciate ligaments in the knee," Levein told The Courier. "It's terrible news.
"He'll see a surgeon, who'll examine the results and decide the next step.
"At Jon's age it's not career threatening - at 26 he is young enough to have the op, recuperate and get back from it, but this is a very serious injury.
"Cruciate operations are common occurrences nowadays, but double cruciate ops aren't. He's looking at a year out and that's such a shame because he's a fantastic boy.
"It's sad when anyone suffers an injury like this. It's doubly sad when it happens to the type of lad he is."