Michael Beale has admitted the injury to Rabbi Matondo could be a "bad one".
The Rangers winger was forced off in the first half of the 1-0 win over Motherwell after taking a knock to the outside of his knee.
In his post-match press conference - citing the knock - Beale explained: "It doesn’t look like a good one".
He added: "Rabbi today we think that might be a bad one. He’s taken a blow on the outside of his knee. That’s the information I was given."
It's a blow for Rangers with Tom Lawrence ruled out before kick-off due to a calf issue picked up against Real Betis.
The Welshman had come off against the Spanish side with suspected cramp before the problem was diagnosed to be more serious.
Beale explained: "Tom thought he had cramp and wanted to continue in the game but we didn’t take a risk. The next day he woke up and couldn’t walk so he has gone for a scan. He won’t play this side of the international duty. He has a problem with a calf.
"The international duty sounds like it’s longer because that is a two week break but he will return with Todd and Nico and Danilo. Kieran might be back in the middle of the week to play at the weekend but obviously he’s lacking a bit of fitness."
