The Hoops manager has been strident in his position that the on-loan Hoops striker would be best served not playing against his parent club.
However, the 24-year-old striker from Sierra Leone arrived in Glasgow for the first leg, with the Swedish club's boss Jorgen Lennartsson reiterating that he will play if required.
Lennon, speaking at the pre-match press conference at the club's Lennoxtown training complex, is now preparing for a "strange sort of scenario."
"I am not going to make a big song and dance about it but the reality of it is, there is a big possibility that Mo could play," he said.
"If he plays, he plays and we are preparing for it as if he is playing.
"You would probably need to ask him how he is feeling more than me.
"We made our feelings pretty clear over the last week or so but we have to respect Elfsborg's decision.
"I am trying to do what's best for Celtic and the Elfsborg manager is trying to do what's best for Elfsborg.
"There is a good relationship between the two clubs, I just think it puts Mo in a very difficult position.
"I wouldn't like to be in that position myself, put it that way.
"I am sure Mo will know plenty about our players but we have plenty of information on Elfsborg.
"I watched them at the weekend and Johan (Mjallby, Celtic's Swedish assistant) knows Swedish football very well so we will be well prepared for them."
Parkhead midfielder Joe Ledley was quoted as saying that if Bangura "scored the winner and knocked us out of the Champions League, then it would be difficult for him to come back."
Lennon was asked about the nightmare scenario and he recognised the danger.
"We are talking hypothetically so we will cross that bridge if and when we come to it," he said.
"It is a situation that doesn't occur very much in football but we will deal with as best we can."
The former Celtic skipper stressed the increase in quality Elfsborg represent in comparison to Cliftonville, the part-time side from Northern Ireland whom the Scottish champions beat 5-0 on aggregate in the previous round.
"They are the Swedish champions with international players, full-time obviously and 17 games into their season so they are match-sharp," he said.
"They are a good, very well-organised side who pass the ball very well.
"There is a good mixture of youth and experience in their team and they are obviously off the back of winning the title so they come into this season confident.
"I think they are probably putting more emphasis on qualification into the Champions league than their progress in the league, so they are a very dangerous opponent.
"It is a concern that the longer the game goes on we might tire a little bit quicker than they will but I think we have enough quality on our side to give them enough problems."
Lennon, who insisted there had been no second bid from Nottingham Forest for defender Kelvin Wilson, revealed that Derk Boerrigter will be added to his squad if the 26-year-old Ajax forward completes his medical this afternoon.
The Northern Irishman said: "He is the type of player we have been looking for, for a while. "He is a very fast, direct, left-footed player who has goals in him with his left and right foot.
"He is also very powerful. He has good experience and he has played at a high level for the last two or three years. "So if all goes well we will be absolutely delighted to get that over line."