Kingston: World’s fastest man Usain Bolt withdrew from the Jamaican National Olympic Trials on Friday with what he described a mildly torn left hamstring, an injury that could keep him from defending triple gold at next month’s Rio Games.

The reigning world and Olympic champion — seeking his third consecutive Olympic titles in the 100, 200 and 4x100 relay — likely must prove his fitness at a Diamond League meet July 22 in London to have a hope of running in Rio.

The Jamaican athletics governing body allows for medical exemptions if an athlete can show an injury denied a chance to compete at the trials. But Bolt must also prove his fitness and that bid comes in his planned run in three weeks in the city he electrified at the 2012 Olympics.

‘I have submitted a medical exemption to be excused from the 100m final and the remainder of the National Championships,’ Bolt said in a statement posted on his Twitter site. ‘I will seek treatment immediately and hope to show fitness at the London Anniversary Games on July 22 to earn selection for the Olympic Games in Rio.’

The stunning turn of events came after Bolt, the 100m world record-holder in 9.58 seconds, won his 100m semi-final heat after a slow start in 10.04 at Kingston’s National Stadium.

Bolt, who turns 30 on the final day of the Rio Games, then departed well before what was to have been a showcase 100m final against former world champion Yohan Blake, who won the sprint final in 9.95. Nickel Ashmeade finished second in 9.96 and Jevaughn Minzie was third in 10.02 just edging out Asafa Powell who ran fourth in 10.03.

‘After feeling discomfort in my hamstring after the first round last night and then again in the semi-final tonight, I was examined by the Chief Doctor of the National Championships and diagnosed with a Grade 1 tear,’ Bolt said in his statement.

A grade one tear is classified as the most minor of hamstring injuries, usually involving only a muscle strain and just a few days to a week for recovery. Grade two is typically a partial tear with grade three a complete tear that might require months to heal.

Bolt later posted photographs he said was himself being treated on the back of his left leg by a physiotherapist while stretched out face down. A caption read: ‘Starting the recovery process right away.’

Glen Mills, coach for the sprint superstar, said Bolt injured the hamstring in Thursday’s 100m first round after his race was delayed for several minutes. A visibly upset Bolt departed the competition area after that run without talking to reporters.

Mills said physiotherapists worked on Bolt so he was in condition to run again in the semi-finals but Bolt felt the pain again in winning that heat and the decision was made for him to withdraw.

‘We wanted to see if he could finish the day,’ Mills said. ‘But I figured he would be apprehensive.’