Hamilton skipper Michael Devlin will miss both legs of the Ladbrokes Premiership play-off against Dundee United.
The 23-year-old defender had to come off in the first half of Saturday’s 4-0 win over Dundee at the SuperSeal Stadium with a knee injury.
Accies travel to Tannadice on Thursday night before the return leg in Lanarkshire on Sunday for which Devlin would have been suspended.
Boss Martin Canning said: “He had a scan yesterday and we will need to wait and see.
“Hopefully we will get something back today, if not tomorrow, and we will know exactly what’s wrong.
“He will be out for Thursday, he has been hobbling about on crutches.
“He was out for Sunday, he was suspended and was going to miss it regardless.
“It is a blow because he has been great for us all season.”
Canning explained the news could be offset by the return from injury of Greek defender Georgios Sarris.
The Hamilton boss added: “Hopefully we can get Georgios Sarris back for Thursday so it will be like-for-like.”