Celtic face losing the services of Daniel Arzani and Eboue Kouassi for the remainder of the season.
Kouassi was injured against Hearts at Murrayfield on Sunday and has been diagnosed with a knee ligament injury.
Arzani made his debut at Dundee on Wednesday but was taken off.
“We are waiting on the final analysis of the scans but it is unfortunate. It looks like we will have two cruciate injuries,” said Celtic manager Brendan Rodgers.
“If it is the case it will rule them both out for the rest of the season.”
Rodgers confirmed midfielder Kouassi, 20, has damaged the anterior cruciate ligament in his knee.
The Ivorian signed for Celtic from Russian club FK Krasnodar in January 2017 but has made just 12 appearances, five of them this season.
He was withdrawn in the first half of Sunday’s League Cup semi-final victory over Hearts having started against RB Leipzig in the Europa League.
While winger Arzani, 19, made his first appearance against Dundee on Wednesday as a second-half substitute, after joining in the summer from Manchester City on a two year loan.
“It’s hugely disappointing for both boys because they have been on the sidelines working their way through and in the last week they have been given opportunities, and both [injuries] are innocuous really,” Rodgers added.
“One a landing and two, Daniel’s was a twist where his studs stayed in the grass and twisted his knee.
“We’ll assess what’s best for Daniel. He still has to go through the final part of his scan at the beginning of next week hopefully and then there will be a plan put in place for him.”