Aberdeen manager Jimmy Calderwood fears that key duo Jamie Smith and Derek Young may not play again this season.
Smith made his comeback from injury against his Celtic on Sunday, but limped off after 20 minutes while Young has been told his damaged knee ligaments will take several more weeks to heal.
Calderwood told the Daily Record: "We're hoping they won't be out for the rest of the season, but anything we get from them will be a bonus.
"Jamie will see a specialist to get to the root of the problem. He's had injury problems since coming here, but it doesn't look like another hamstring this time.
"Pain is coming from his back and shooting down his leg. It's a very depressing situation for the player, as he'd worked so hard in training to regain fitness.
"Derek has badly damaged knee ligaments and will be out for at least five or six weeks, so it's bad news all round."