Olympic heptathlon champion Jessica Ennis-Hill is expected to be out of action for around 15 weeks, according to her coach Toni Minichiello.
The 27-year-old made the decision to pull out of the upcoming World Championships in Moscow earlier this week because of the Achilles and heel problems she has been struggling with throughout the summer.
Ennis-Hill managed to compete in the Sainsbury's Anniversary Games last weekend in the hurdles and the long jump but was some way below her best, prompting her decision to pull out of Great Britain's squad for Moscow.
And Minichiello says the Sheffield-born athlete is now looking at a recovery period of up to four months.
"Achilles tendons are awkward and there's a period of rest [involved]," he told the BBC.
"If we're lucky then we're looking at a 12 to 15-week recuperation period.
"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."