Hearts striker Calum Elliot faces a lengthy spell on the sidelines with a knee ligament injury.
Elliott, who was making his first appearance of the season, suffered knee cartilage damage during last weekend's defeat to Rangers.
The 22-year-old has been ruled out for up to two months and Hearts boss Csaba Laszlo will now step up his search to bring a new striker to Tynecastle.
"The time frame is not set in stone but it's looking like eight weeks for Calum at the moment," Laszlo told his club's official website.
"He will visit a specialist as soon as possible and he will confirm the best course of treatment.
"This sort of injury normally requires surgery so we'll just have to wait and see and hopefully he can come back as quickly as possible."
Meanwhile, Hearts midfielder Ian Black claims Rangers' Kevin Thomson could have broken both his ankles during Sunday's fiery clash at Tynecastle.
Thomson was shown a straight red card for the challenge early on in the clash and Black admits he was lucky to escape suffering serious injury.
"I saw Kevin coming and I managed to get out of the way as best I could. If I'd been standing with both feet on the ground, I'd probably have ended up with a couple of broken ankles," noted Black.
"I know Kevin is not the type of player to deliberately go and hurt anyone.
"He was late, but he doesn't go out to do that. I know it wasn't intentional.
"He was going for the ball but just timed it wrong. He caught my ankle and it was a sore one."
Black was also unhappy with the award of the late penalty that gifted Rangers victory, insisting Ismael Bouzid's challenge on Stevie Naismith was outside the area.
"Looking at the paper and the photos, the evidence shows it was outside the box and we were hard done by," added Black.
"It was a slap in the face which we certainly didn't deserve going on the first-half performance."