The Greece striker came off with a hamstring problem during the 4-1 Clydesdale Bank Premier League win over Kilmarnock at Parkhead on Wednesday night and will have a scan on Thursday morning to ascertain the extent of the injury ahead of the February 12 visit of the Italians.
Neil Lennon's joy at going 15 points clear of Inverness at the top of the SPL table was tempered by his concern over Samaras although the Celtic boss is more confident that defender Emilio Izaguirre, who also went off before the break with a knee injury, will recover quickly.
He said: "Emilio should be okay. He just felt a little bit of tightness at the back of the knee.
"Georgios, we think, may have a slight strain but he will be scanned and we are hoping it is not too serious.
"It is two weeks until Juventus and if it is more than a mild strain then it will be a concern.
"At the minute it doesn't look too bad but the scan will reveal more."
Adam Matthews grabbed a double, his first two SPL goals of the season, while substitutes Joe Ledley and Anthony Stokes helped themselves to a goal each against a youthful Killie side whose counter came from a former Celt, Cillian Sheridan.
Lennon was glad to see Stokes on the scoresheet as he continued on the comeback trail after recovering from an ankle injury which had kept him out since August until recent weeks.
The former Celtic skipper, who expects striker Gary Hooper still to be at Parkhead when the transfer window closes on Thursday night, after revealing that a third bid from Norwich had also come up short, said: "I am delighted that he scored. That will give him a huge shot in the arm because he worked really hard for that.
"There is a bit more to come and that will come with games."
Celtic ended up comfortable winners but there was a moment of controversy in the first half with the game goalless.
The visitors were raging when teenager Ross Barbour appeared to have squeezed the ball over the line in the 37th minute only for referee Calum Murray to wave play on after Hoops keeper Lukasz Zaluska retrieved the situation.
Killie assistant Jimmy Nicholl said: "The ball was apparently over the line, I don't know but our boys were going absolutely ballistic because the boys in the box swore it was over the line.
"Barbour came in the back and scored and the kid was adamant the ball was over the line, that's why our boys were going ballistic.
"I was disappointed for them because it should have been a goal but there were positives apart from the result in the end."