Usain Bolt Jamaica
Usain Bolt reacts after his 100m heats in the Jamaican trials, June 30, 2016Reuters

The only thing that can stop Usain Bolt from clinching a third straight title in the sprint events of the Olympics is injury. Having struggled with niggling problems for a while now, there is a big question mark over the great man's fitness, and those worries only increased after Bolt withdrew from the Jamaican trials owing to injury.

Having qualified for the 100m final of the Senior National Championships, the official Jamaican trials for the Olympics, Bolt decided against competing in the race, citing a hamstring problem. While that means he cannot qualify for the Olympics, which begins on August 5, via the event, Bolt can still compete in Rio with a medical exemption.

"After feeling discomfort in my hamstring after the first round last night and then again in the semifinal tonight I was examined by the chief doctor of the National Championships and diagnosed with a Grade 1 tear," Bolt said in a statement on Friday.

"I have submitted a medical exemption to be excused from the 100m final and the remainder of the National Championships. 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."

Yohan Blake went on to win the 100m in the trials and qualify for the Rio Olympics, and being Bolt's good friend, he was asked about the sprint legend's condition. Blake did his best to play down fears his compatriot could miss the Rio Olympics.

"No doubt, no doubt, no doubt," Blake said when asked if Bolt will be there in Rio to defend his titles. "It's just a caution measure. He's good. Just being cautious."

If fully fit, Bolt, who put up photos on Instagram and Twitter saying his recovery process had already begun, will be the overwhelming favourite to win the 100m and 200m titles in Rio, races he won in the 2008 Games in Beijing and the 2012 London Olympics.