Former midfielder Stiliyan Petrov believes the next Celtic manager must be an instant hit and push for the title.
It will be a massive summer in Glasgow's east end with the squad facing a massive overhaul following the failed 10 In A Row bid.
With Eddie Howe and Roy Keane the current frontrunners for the job, whoever steps into the top job will have task to catch champions Rangers.
However, Petrov doesn't believe either man will be given extra time to get things right due to the scale of the job following the collapse this term.
The Bulgarian told The Celtic Huddle podcast he had to learn quickly that without silverware you are at risk of leaving Parkhead after his move to the club in 1999.
He said: “I’m sorry to say this but I don’t think you can be a Celtic manager and say this is a rebuilding project. There’s no such thing.
“I came from a foreign country and I had to learn very quickly and understand the DNA of the club, the demands of the fans.
“When you are the manager, you don’t have time to do that, especially in today’s football industry. You don’t have time to rebuild.
“If you manage a club like Celtic, you have to win. You have to win as much as you can.
“If you don’t, you’ll lose your job. This is a job where people have to go in expecting to win. It’s not a rebuilding process. There’s no rebuilding time.
“That’s unfortunately the reality but you have to face it.”
Petrov also heaped praise on former teammate Keane and believes that the Irishman or Howe would be able to rival Steven Gerrard's side next term.
He continued: “ Roy Keane and Eddie Howe are two very strong candidates, two candidates who can provide a lot to the Celtic fans.
"Both of them are completely different. Roy is fearless. We had the chance to play with him, we know how fearless he is.
“He is strongly opinionated. He knows what Celtic means and what the demands are.
“Eddie Howe has done a great job down in England and has had a tremendous amount of success with Bournemouth. Everyone talks so highly of him.
“So I think it’s two candidates with a very strong possibility to take Celtic to the next level."
