Rhys Williams has withdrawn from this weekend's British Athletics Championships in Birmingham due to a heel injury.
The 31-year-old was due to race in the 400m hurdles at the event, which doubles up as trials for this summer's World Championships.
Williams has endured a frustrating year after serving a ban for doping, and he admits that running with an injury could have done his chances of reaching Beijing even more harm.
"I wasn't going to run this weekend unless I was fit and ready," Wales Online quotes Williams as saying. "I raced in 2011 when I was injured in the week and I regretted it by under-performing.
"So I won't race unless I can perform properly. Sometimes you can take one step forward and two steps back. It is better to have that few days' extra rest and get back the following week.
"I have injured my heel in training. If I ran I would have to have had an injection in my foot. You have to be sensible."
The top two athletes this weekend will book their place at the World Championships if they run the qualification time of 49.50s.
