Samaras has been a key part of the Hoops' European journey this season but will have a scan on Thursday to see if he is able to feature in the first leg at home to the Italians on February 12.
Celtic boss Lennon is more confident that defender Emilio Izaguirre, who also went off before the break with a knee injury, will recover quickly.
Lennon 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 tomorrow 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 tomorrow."
Killie assistant Jimmy Nicholl insists the Rugby Park players were incandescent when Barbour's 'goal' was not given.
He 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."