The 29-year-old midfielder spent seven years at Old Trafford, but saw his spell under Sir Alex Ferguson brought to an end by a long-standing knee injury which caused him to miss the entire 2005/2006 season.

After potential moves to Celtic and Manchester City fell through in the summer, Bolton coach Sam Allardyce stepped in with a one-year deal.

"I'm now in the best condition I've ever been," said Fortune.

"The injury was obviously frustrating and you don't want anything like that to happen.

"But I never had any doubts I would return, even after Manchester United released me. I admit it was difficult to leave because I had good times there.

"But I've come to learn you can't get too attached to things. You have to move on sometime, and I've moved on to a great club.

"My fitness is now good, and that's credit to the medical staff who have worked with me all summer.

"With other clubs there was a negative approach, but with Bolton they were positive. There was never any doubt about getting me fit."

Fortune is confident his injury nightmare is now behind him and is determined to make the most of his one-year deal at the Reebok Stadium.

"Nothing is set because I have to perform well to get into the team," he said.

"I know I now have an opportunity here and I'm looking forward to the challenge. Hopefully I can stay here longer, but that's down to me to play good football, and most importantly help the team."

Allardyce insists Fortune is ready to prove himself in the Premiership again after 76 appearances for United.

"He comes in every day and looks a happy man, and that's a great sign for me," said the Bolton boss.

"What he gives us is his experience after seven years at Manchester United, and after speaking to Sir Alex and knowing the way he plays the game, he is a tough character."