St Mirren defender Conor McCarthy will undergo a scan on Monday morning after limping out of Saturday’s 1-1 draw with Livingston.
The Irishman landed awkwardly after contesting a ball wide on the touchline and was replaced by Charles Dunne.
And Saints manager Jim Goodwin admits he fears the worst.
He said: “It looks serious at the moment. He wouldn’t come off if it wasn’t.
“He went up for a header and landed awkwardly on his ankle, although the problem might actually be higher up his leg.
“We’ll see how it settles down and look to get it scanned on Monday. Hopefully it will be similar to the Jamie McGrath one where you feared the worst initially but then it’s not as bad as first seemed.
“I thought Charles was excellent when he came on considering he’s not played a great deal of football in the last couple of months. He’s not a bad replacement to have coming on.”
Goodwin admits he took little consolation from his team entering the top six on Saturday, believing they have thrown away six points in recent games by drawing instead of winning.
He added: “I sound like a broken record most weeks. But we drew with Motherwell when we should have been out of sight by half-time, we drew at McDiarmid Park two weeks ago and Callum Davidson admitted after the game that we were the better team and should have won, and again on Saturday.
“So that’s an extra six points that, in my opinion, we should have. But I can’t keep saying that as people will be fed up of hearing it. But the difference of not having those six points is incredible in how the league table looks.”
Meanwhile, Livingston boss David Martindale admits he was hoping Nicky Devlin would pass it just before he scored the equaliser at St Mirren.
Jamie McGrath’s brilliant effort looked like bringing Livi’s undefeated run to an end.
But Devlin was in the right place at the right time to thump in a spectacular effort – much to his manager’s surprise.
Martindale said: “I was shouting, ‘Pass it, Nicky’. You haven’t seen his shooting in training! But what a strike – phenomenal.
“He said he was thinking about taking a touch but he just hit it. Alan Forrest was unlucky with the original shot, but it was a fantastic strike from Nicky.
“Jak Alnwick didn’t have a chance. It was straight into the side-netting. It was a great goal but so was Jamie McGrath’s, so well done to the players.”