Celtic skipper Scott Brown has been ruled out of the Champions League last-16 return trip to Juventus next week.
The 28-year-old is nursing an ubductor problem the extent of which is still to be determined.
The Hoops will also be withouht defender Mikael Lustig who faces up to three weeks on the sidelines with a thigh problem.
Brown, Lusting and Charlie Mulgrew will also all miss Wednesday's Clydesdale Bank Premier League at Motherwell.
"Oh yes, I would imagine so," Lennon said when asked whether Brown would miss the clash against the Old Lady.
"He (Brown) is out indefinitely.
"We are still waiting to hear from the specialist, whether he requires surgery or not and I am hoping that we will get a definitive answer by the end of the week.
"Lustig is still out and Charlie Mulgrew (glute), they are the only three absentees
"Lustig is out for two to three weeks, it is bone bruising so it could even be longer.
"So I imagine he will miss Juventus. We are hoping Charlie will be fit for Juventus and the game at the weekend.
"Kris (Commons) is back from his virus and Lassad (Nouioui) has had a bit of a virus but he is in the squad."