Neil Lennon is hanging on to his job as manager after his side crashed out of the Scottish League Cup at home following a defeat to Ross County on Sunday.
With only two wins in their last ten games, some Celtic fans have mounted pressure on the board to act and show Lennon the door soon.
O’Neill and Strachan have been linked with the job and McManus believes either of them would be a good appointment for Celtic for the short term.
He feels that either of them would be able to get a better tune out of the players because of their man-management skills and provide an instant boost, which is needed if Celtic are to stop Rangers from ending their dream of winning ten-in-a-row this season.
McManus said on PLZ Soccer: “I feel you have definitely got to bring someone in, if Celtic do, who knows how to win things as manager and who knows the goldfish bowl of Glasgow.
“And that would be Martin O’Neill or Gordon Strachan – only short-term.
“Both of them are very good man managers, and I think they would come in and you would get an immediate adrenaline in the players, and you would get them playing for you again.
“I think you would get a bit of buzz about the place again and you would get a lift from the calibre of those two guys.
“I am not saying they are answers for the long term, but from now until the end of the season, either of them coming in, particularly Gordon Strachan, would give Celtic at least a chance of stopping Rangers.”
At present Celtic are continuing to back Lennon, who is preparing the side for Thursday’s Europa League meeting with AC Milan.
