Olympic champion Usain Bolt has pulled out of the Monaco leg of the Diamond League later this month, his coach said on Thursday.

“Arising from Usain’s participation at the national trials in Kingston last weekend where he had a slight problem … I’ve had to withdraw him from the Diamond League meeting in Monaco on July 20 to give him sufficient time for treatment and time to train and prepare for the Olympics in London,” Glen Mills said in a statement.

He did not elaborate on the Jamaican sprinter’s “problem”.

Bolt will defend his 100 metres, 200 and 4×100 titles at the London Games which start on July 27.