Motherwell boss Maurice Malpas fears Keith Lasley faces a lengthy spell on the sidelines.
Lasley picked up a knee injury during Motherwell's 1-0 win over Inverness Caledonian Thistle on Saturday.
Malpas believes Lasley could be out of action for two months with the knee problem.
"It is a big disappointment and he could be out for a couple of months, but, hopefully, it is only ligament damage and not cartilage," said Malpas.
"I think he hurt himself in a tackle during the first-half and got it iced at half-time.
"But he has hurt himself even worse and it is a blow because we need our best players fit and he had been performing well with Brian Kerr."