The 27-year old right-back has had problems with his knees in the past and again it has flared up with the Hoops sending him to London to find out more.
Lennon says if he required surgery he could be out for at least four months and as many as six.
"Mark Wilson is in London seeing a specialist regarding surgery in his right knee," Lennon said.
"It could be a microfracture and need surgery which would probably rule him out for four to six months.
"He has had this ongoing problem for a long time. It has got to the stage where he feels that he's struggling to play two games in three or four days.
"He's in a lot of pain, constantly now.
"We always knew it would come to this, we were just hoping he could hang on for a bit longer. But he feels now that he needs to go and get another opinion. It might come back that he won't require surgery.
"He has had problems with both knees. It is one of those unfortunate circumstances in a player's career. He has been fantastic since he came in through the door, a true professional and played through a lot of pain which people don't know about.
"He has had a lot of injuries but this one, you just knew one day it would come back to bite us."