Paralympic champion Jonathan Fox will miss next month's IPC Swimming European Championships in the Netherlands because of a shoulder injury.
Fox, 23, has been having treatment but needs more time to recover.
The Cornwall man won S7 100m backstroke gold at London 2012 and is also the World and European champion.
"I'm really disappointed not to be competing but this is the right decision to make sure it doesn't reoccur," he said.
"I've been swimming competitively for over 10 years and this is the first time I've had to make the really hard decision to pull out of a competition.
"I now have to focus on working on my weaknesses so it doesn't happen again and stop me going to next year's World Championships in Glasgow or Rio 2016."
The European Championships run from 4-10 August in Eindhoven.