Celtic striker Vakoun Bayo has undergone a knee scan and "may require surgery" that will sideline him for six weeks, says manager Neil Lennon.
Captain Scott Brown is also an injury worry, having been taken off with a thigh problem in the second half of the 2-0 win over St Mirren on Wednesday.
With Leigh Griffiths not having played since August, Odsonne Edouard is Celtic's only fit striker.
"Bayo's seeing a specialist. It's not good," Lennon said.
"So if he does need surgery we are looking at maybe six weeks. Leigh is back training tomorrow but we'll have to wait and see his condition.
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"Scott tweaked his thigh. He came off straight away. We didn't want to take any chances. We will have to see how it settles but we are hoping he will be okay."
Lennon, who said this week he could look to sign another striker in January to ease the burden on Edouard, hailed "priceless" winger James Forrest for inspiring his side's second-half improvement at home to St Mirren.
The champions struggled to prise open a well-drilled defence until Mohamed Elyounoussi bundled home a rebound at the start of the second half.
Forrest, fresh from extending his contract to 2023, then ensured Celtic stayed top of the Scottish Premiership on goal difference with his 10th strike in 22 club appearances this season.
"He was brilliant," Lennon said. "We gave him a new deal and I don't care how much we pay him, he is priceless to me.
"His inventiveness, intelligence was there for all to see. It was a brilliant goal and his all-round game was exceptionally high again.
"We needed more oomph and I certainly got that second half and we could have won by a lot more."