Hearts winger Andrew Driver looks likely to miss the rest of the season with a torn thigh muscle.
The 20-year-old pulled up injured in the first half of the Clydesdale Bank Premier League draw at St Mirren on Saturday
And scans have shown a muscle tear in his left thigh, which will take around six to eight weeks to heal.
Hearts caretaker boss Stephen Frail said: "It's very disappointing and obviously a real blow,
"He will be out for a number of weeks and it's another setback for the player, who has had a bit of a stop-start season due to injury.
"His season has been interrupted by injury and it's frustrating for us all as he had been looking very good in parts."
Frail had better news on the injury front with midfielder Laryea Kingston in line to return from a foot injury against Falkirk at Tynecastle on Saturday.
Kingston last played for Hearts in a 1-1 draw against Celtic on December 1 and suffered an injury while on African Nations Cup duty.
"Laryea is a quality player and has a real chance of making the weekend, which is good news," Frail told the club's official website.
Kingston was yesterday named in the Ghana squad for their friendly against Mexico at Craven Cottage on Wednesday.