Celtic star James Forrest is set to miss next month's clash with Rangers with an ankle knock but Albian Ajeti could return for the crunch clash.
The Scotland international picked up the injury in last week's Europa League win against Riga and will miss the playoff clash with Sarajevo on Thursday night as will the Swiss international.
Lennon insists there was no definite time scale on his recovery and, asked if he would be out for the Rangers game at Parkhead on October 17, he said: "Yes, I would imagine so.
"We are a little concerned about James because it is a sore one and we haven't got a length of time on it just as yet."
Ajeti picked up a hamstring injury scoring against Hibs but Lennon is hoping he will be back for the visit of Steven Gerrard's side.
The Parkhead boss said: "Ajeti won't travel, he's not fit and not available, neither is James as we touched on before.
"We are hoping Albian will be fit for the Rangers game in a few weeks times.
"James is going to be a but longer but we haven't got a certified time on that yet.
" Christopher Jullien is fit and back in the squad so only Albian is the only absentee from the weekend.
"In terms of injuries, we have been pretty okay so far this season."
