Bangura has failed to make the impact expected of him after moving from Swedish club AIK in 2011 for £2.2m, an injury plagued spell failing to bring a solitary goal in 16 games.
The Sierre Leone internationalist returned to AIK on loan in 2012 and then spent 2013 with IF Elfsborg on a similar deal, playing against Celtic in the third qualifying round of the Champions League. He returned to Glasgow earlier this month hoping for a fresh start but the 24-year-old is likely to be sold in the coming days or sent back out on loan.
"Bangura could leave in the window," he said. "We're clearing the staff a little bit and have sent some of the younger ones on loan to gain experience. But in Mo's case, it's in his best interests to go and play first-team football. It's reasonable to say that he doesn't have a future here.
"It just hasn't worked out for both parties. These things happen sometimes in football. You're never going to get every signing right. Every manager, even the greats, have made a mistake or two along the way. Mo needs to get out and play because it's going to be restrictive here."
Lennon, who has let Bahrudin Atajic go on loan to Shrewsbury Town and Callum McGregor return to Notts County, still hopes to add to his squad before the window closes on Friday. He said a move to sign an unnamed foreign striker had "hit the buffers" but was coy on the prospects of adding Leigh Griffiths or Robert Snodgrass to his group.
"We hit the buffers yesterday on one," he added. "It ended quite abruptly, which is disappointing because we thought he was a very, very good player and we had done a lot of work on it. We will see what the weekend and next week brings, but I'm hopeful we will get one or two in. We've not spoken to [Snodgrass's] representative or his club, so the stories must be coming from down there and I can't say [Griffiths is on a list] but he is highly thought of."