Wayde van Niekerk: Olympic champion could miss rest of Diamond League season
Olympic champion Wayde van Niekerk could miss the rest of the Diamond League season after suffering a "minor setback" in his recovery from a knee injury.
The South African, 26, had returned to competition in February after more than a year out, but a scan has revealed a further "bone bruise".
Van Niekerk, who is the current Olympic and world 400m champion, has been ruled out for about six weeks but hopes to be fit for September's World Championships in Doha.
"It's very disappointing," he said. "I've been pushing myself too hard in training so that I can make a memorable comeback.
"Now I'm working towards the goal patiently and I will review my competition schedule with my team, and together with my coach, we will decide where and when to race."
The South African suffered the injury in October 2017 during a celebrity touch rugby match.
The world and Olympic 400m record holder, made a winning return to action in February after almost 17 months out.
If fit, Van Niekerk, who won 400m gold at Rio 2016, will be bidding for his third consecutive world title crown in Qatar after being given a wildcard for the event.