Olympic heptathlon champion Jessica Ennis-Hill is out of the World Athletics Championships in Moscow in August after withdrawing due to a heel injury.
Ennis-Hill has competed just twice this season, at a low-key meeting in Loughborough and the London Anniversary Games last weekend, due to the problem.
The 27-year-old's return had raised hopes she could travel to Moscow but along with coach Toni Minichiello has instead decided to allow the ongoing problem to heal.
"It's not been the easiest or simplest of decisions," Minichello said.
"The pain management did improve, and Jessica was able to compete in London, but the next few days have not seen enough improvement that would have made completing the two day, seven events of the Heptathlon possible.
"I've also had to consider if competing at the world championships would cause further damage, making any rehab more difficult. There are nine global medals up for grabs over the next three years not including Moscow. So a long term view has been taken."
Coach Minichiello added: "The next aim will be to unload the Achilles for a week or so and during this time gather more opinions about all possible recovery strategies.
"After which I will pull the team together to examine the way forward, but also examine how it happened in the hope we can avoid this going forward. The aim will be that any recovery process will make an indoor season possible in 2014."
Performance coach Neil Black said: "I know this has been a tough decision for Toni and Jess but I feel it is the right one with the long term view.
"They've worked hard to bring her to a point where she was close to competing and it was great to see her in action last weekend, but no-one wants to see her competing in pain, and we look forward to seeing her wear the GB & NI vest again in 2014."
Ennis-Hill's hopes of regaining her world title had initially been given a boost after the news that the defending champion from Daegu, Tatyana Chernova, had pulled out with knee-ligament damage.
The Olympic champion from London 2012 becomes the latest high-profile athlete to miss the championships in Russia next month, with 800m world record holder David Rudisha and Jamaican sprinter Yohan Blake injured while Asafa Powell and Tyson Gay both await potential anti-doping charges.