Cook brought Mancini to City and wrote in the Daily Mail: "There is not a more competitive man than Roberto Mancini. He is his own biggest critic. That's a passion you have to admire and you have to love that. But the game is judged on results.
"It is judged on the ambition of owners. If the owners don't feel results are what they want then a different conversation will be had. I am a great fan of Roberto - I brought him into the club for the right reasons and he executed on the reasons we brought him in for. Everyone has a lifespan.
"I wish him all the best because Manchester City's trophy cupboard is a little more full than it was before he got there."