BOXING:Vitali Klitschko faces an uncertain future after being forced to cancel his comeback fight against Jameel McCline due to a back injury.

The former WBC heavyweight champion, who had retired in November 2005 before announcing his ring return earlier this year, was to take on the American veteran in Munich on September 22nd.

However, he suffered severe back pain at the beginning of Saturday morning's practice session which forced him to undergo emergency spinal disc surgery later that day in Innsbruck, Austria.

"Instead of practising I landed in hospital," he said. "I picked up the injury during the warm-ups. I was in superb shape. I did not see any dark clouds in the sky."

Klitschko revealed the surgery was successful.