Charlie Nicholas has challenged Celtic chief Dermot Desmond to show he still has the stomach for a fight.
The pundit and former Parkhead star urged the club's billionaire majority shareholder to "stand up" and show disillusioned fans he's determined to rebuild the club.
He fears Rangers, on the verge of clinching the title, will continue to pull away until Celtic get their act together again.
Desmond responded to the threat of the Ibrox club's return by appointing Brendan Rodgers in 2016 and Nicholas wants him to show that passion and ambition again.
He wrote in The Express: "Celtic fans need to see and hear if Dermot Desmond still has the hunger and desire to take the club forward.
"Neil Lennon has left and Peter Lawwell is leaving, so Desmond's voice is the only one that matters now.
"Dominic McKay is an accountant and when he comes in from Scottish Rugby to replace Lawwell as chief executive it will be to balance the books.
"McKay won't have the same power as his predecessor when it comes to transfers, influencing club strategy and controlling the spending.
"There are strong rumours that a technical director will come in. That is also well and good but until we hear from the man at the top it doesn't really matter what anyone says or thinks.
"Hoops supporters need to see that Desmond has a plan and the passion to keep taking the club forward.
"The Irish tycoon might officially be a non-executive director but everybody knows he is the voice and the decision maker at Parkhead.
"Desmond once had a go at me because I accused him of treating the club like a toy.
"Now it is time for him to stand up. Not to me or the media, but to the heartbeat of the club - the fans - to tell them how Celtic is going to move forward from this season.
"They need to get a structure back in the club and get the hardcore of the support back on track.
"Until that is done then Rangers will continue to grow and get stronger while Celtic will just get weaker and slip further and further behind.
"If Desmond has lost interest then the possibility of a new purchaser coming in would concern a lot of fans.
"They only have to look at what happened across the city when they were taken over by so many wrongdoers.
"Celtic aren't in freefall, but they are not in as good a financial position as they have been in previous years.
"The appointment of the next manager could be a real indication of the level of Desmond's ambition."
Nicholas wants his old club to look outside the box when appointing the man to replace Neil Lennon, suggesting the likes of Xavi, Vincent Kompany and Xabi Alonso should be considered.
He continued: "Celtic should be speaking to the agents of Xavi, Vincent Kompany and Xabi Alonso to gauge their interest in the job.
"I have seen Frank Lampard mentioned as a potential candidate, while Thierry Henry's name has also been thrown into the mix, but I am not sure if either of them would be keen.
"I just want the club to ask the question and show a bit of ambition. If they don't then they will appoint someone like Roy Keane or Steve Clarke.
"It all comes back to the owner and it is now up to him to deliver.
"Is Desmond truly determined to get Celtic back to the top?"
