``It's unfortunate, very sad for Michael,'' said England chairman of selectors David Graveney in an interview with BBC Radio from Lahore, where he was with the squad, today. ``Such is the injury it can recur at any given time and unfortunately it's back to square one and he faces quite a lengthy rehab treatment.

Atherton, who was named in the World Cup squad pending a fitness test, had been at England's Sharjah training camp in Lahore, Pakistan, for less than 24 hours before ruling himself out.

Atherton reportedly told Graveney on Tuesday he was not fit enough to continue after missing a training session. He will return to England within days for treatment, while selectors meet urgently to name a replacement before the March 31 World Cup squad registration deadline.