Kilmarnock interim manager Gary Locke fears he will lose defender Mark Connolly to a serious shoulder injury.
The Irishman had to be substituted for debutant David Syme in the 42nd minute of a 3-3 draw with Inverness Caledonian Thistle.
Locke, who succeeded Allan Johnston as boss, will await scan results on the extent of Connolly's injury.
"We're really disappointed and it's not looking too positive at the moment," Locke told BBC Scotland.
"It's a huge blow for us because he's a very important member of the team. Young David Syme goes on and makes his debut today which is good, but I think we'll be missing Mark Connolly now for a number of weeks.
"We've got quite a few injuries at the moment but I'm certainly not going to use that as an excuse. We had a lot of youngsters on the bench but we've got a really good youth academy here."
Midfielder Jamie Hamill and left-back Chris Chantler are two other first-team regulars missing through injury for Killie.
Locke was more positive about the way his side took a point from Caley Thistle, with Nathan Eccleston, Craig Slater and Tope Obadeyi replying three times keep things level.
"The character of the squad is tremendous," said Locke, who is unbeaten in three games in charge. "To come from behind three times, and twice last week, shows you that they've got a bit of spirit about them.
"They didn't let their heads go down and battled back. We've got a lot of characters in the dressing room and they are very united.
"I've just tried to work on one or two things on the training pitch and the boys are putting that into practice. The results have been pretty decent of late."
Inverness Caledonian Thistle manager John Hughes expressed his "bitter disappointment" at only taking a point from the match, which dents their push for a European place.
"We need to be a bit more ruthless and manage the game better, just to keep that back door shut," he told BBC Scotland.
"We were defensively poor from the front. But we'll take that dunt on the chin and hopefully come back from it on Tuesday night (against Dundee United).
"We've got a few trialists in at the moment and hopefully we can get a new face in by next week."