Falling 18 points behind leaders and Old Firm rivals Rangers with eight games to go has prompted the club hierarchy to act – after a season of slip-ups, sub-par performances and protests.
Speculation and rumour has been rife on the manager’s future for some time – and the betting markets on his successor have been ever-changing.
We look at who could be stepping in for the former Hibs and Bolton boss as his second spell in charge at Parkhead comes to an end.
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5. Rafa Benitez
Another whose name has not been far away from links to the club, sources close to the Spaniard say he isn't looking to move to the east end of Glasgow and is keen on a break from football until June since leaving the Chinese SuperLeague. Also linked to Newcastle return. (STR/AFP via Getty Images) Photo: STR
6. Roberto Martinez
Linked with a role at Celtic in years gone by, current Belgium manager has a Parkhead link by his side in Shaun Maloney. Would surely fancy a crack at Euro 2020 with favourites Belgium first, but ticks the right boxes for fans and has a strong CV. Photo: JOHN THYS
7. Jack Ross
Another strongly rumoured at one stage of the season, has built a strong foundation at Easter Road. Would be following Tony Mowbray and Lennon himself westwards along the M8 in recent times but fans are keen for a bigger name despite commendable turnaround at third-placed side. Photo: Mark Scates - SNS Group
8. Alex Neil
Ex-Hamilton and Norwich boss has a commendable track record but again, fans are keen for a bigger name. Surged in betting market on back of Celtic's talks with Preston defender Ben Davies but recent form at Preston underwhelming. Photo: SNS Group Rob Casey