London - Jessica Ennis-Hill's coach expects the Olympic heptathlon champion to be sidelined for up to four months with the Achilles problem that forced her withdrawal from this month's world championships.
Ennis-Hill pulled out of the August 10-18 championships in Moscow on Thursday, blaming her absence on the injury she has been struggling with for the past few months.
And on Friday the 27-year-old's coach Toni Minichiello told the BBC: "Achilles tendons are awkward and there's a period of rest (involved).
"If we're lucky then we're looking at a 12 to 15-week recuperation period."
Ennis-Hill was one of the stars of the London Olympics last year and her victory in the seven-event competition made her one of Britain's most recognisable sports stars.
She competed at last month's Diamond League/Anniversary Games meeting at the Olympic Stadium in east London with her ankle heavily strapped, finishing fourth in the 100m hurdles and eighth in the long jump.
Minichiello reflected: "When she didn't respond well after the London Diamond League, the position was that it didn't make sense and you're probably going to cause her more damage and lose the remaining years of her career to struggling with the injury.
"As a coach I'm not prepared to take that kind of risk so decisions are made and we pulled her at that stage."