Carsley picked up the knock during the recent FA Cup tie with Nottingham Forest at the City Ground.

City manager Alex McLeish initially declined to put a time limit on how long the 34-year-old would be out of action.

But, on the day McLeish unveiled new midfielder Michel, the former Scotland manager conceded Carsley will out of action for another six weeks.

It is a blow for Blues as Carsley has been experienced back-up for the first-choice partnership of Lee Bowyer and Barry Ferguson.

And it puts more onus on Michel to adapt quickly to life in the Barclays Premier League should either of that duo also be ruled out.

daily treatment

McLeish said: "You are probably looking at Lee being out for six weeks.

"He has not had an operation, he is just getting daily treatment. His ankle is in a boot, is stabilised and that is going to help him more.

"But he doesn't need any surgery."

McLeish is hoping Michel will be firing on all cylinders for next season but wants him to be ready to step into the current side as quickly as possible.

He said: "Is he more for next season? If he adapts faster than that, then that's a bonus.

"But, if anything should happen to my midfielders, then I want him to be be right to come in and he has got to adjust quickly.

"He can't be of a mindset that he is just breaking himself in for next season. He has got to be here saying 'I want to challenge Ferguson and Bowyer."'