Cape Town - South African star swimmer Chad le Clos has pulled out of the heats of the men's 50m butterfly on Day 1 of the FINA World Championships in Gwangju, South Korea.
Le Clos didn't swim in the event in 2017, but did take part in 2015 where he finished 14th in the semi-finals - failing to make the Top 8 who progressed to the final.
Le Clos is reported to be nursing a groin/hernia injury which may require surgery after the championships.
However, Le Clos, a four-time Olympic medalist and 14-time world champion is still expected to swim his primary events - the 100m and 200m butterfly.
Le Clos is also slated to swim the 100m freestyle.
Meanwhile, South Africa also scratched from the men's 4x100m freestyle relay heats scheduled for Day 1.
Despite Le Clos' absence, there are a number of other South Africans due to feature on Day 1.