London: Fitness concerns, an early morning car crash and losing over both the 100 and 200m to the same Jamaican rival have raised serious doubts about Usain Bolt's ability to defend his Olympic sprint titles.
The 25-year-old transformed the world of athletics when he scorched to victory in both sprint events at the Beijing Games in then-world record times.
Bolt, who is due to hold his first pre-Olympic press conference at 5:00pm (1600 GMT) in London on Thursday, bettered his Olympic form at the 2009 Berlin worlds, setting current world records in the 100 and 200m of 9.58 and 19.19sec.
But a sensational false start in Daegu last August saw him cede his world 100m crown to compatriot Yohan Blake, who recently eclipsed Bolt in the Jamaican Olympic trials, notably inflicting on his training partner a first loss over 200m in more than four years.
Bolt, standing 1.96m (6'5") tall, has also struggled with leg and back problems in recent weeks, but Jamaican team doctor Winston Dawes said he expects Bolt to be in prime shape by the time track and field events start on August 3.
"He's back fully. He has been training very, very hard and his performance is on track," Dawes told the BBC on Wednesday.
"We expect he'll be fully fit by the time the Olympics come around. He had some slight cramps in his legs. He had had an accident before, so that might have shaken him up a little."
Bolt walked away from that one-vehicle accident reportedly uninjured, but Jamaican police were left waiting to hear from the triple Olympic sprint champion after he provided what they said was a "sketchy" statement.
Bolt had at least passed a breathalyser test to prove he was not under the influence of alcohol at the time of the crash that left his BMW sports car damaged.
Back on the track, the accident followed his slowest 100m in three years at Ostrava in May, and after being beaten by Blake in the Jamaican trials, Bolt withdrew from the Monaco Diamond League meeting citing a "slight problem".
That sparked intense injury speculation and talk that the world's fastest man, and athletics' hottest property, was "fallible".
Realistically, a Bolt carrying a nagging back problem is fallible only when it comes to a handful of sprinters capable of running sub-9.90sec times in the 100m.
"I wouldn't bet against Bolt," said Michael Frater, captain of Jamaica's Olympic team, and a key member (alongside Bolt) of Jamaica's world record-breaking 4x100m teams, both in Beijing and Daegu with times of 37.10 and 37.04sec respectively.
"He (Bolt) is a special athlete."
Bolt was a disappointing no-show at the Team Jamaica open day at their training base in Birmingham.
Another absence from the show-boating Bolt in the British capital will have Olympic organisers, sponsors and fans alike quaking in their boots.
Not offering glad tidings was the horse part-owned by Prince Harry and named "Usain Colt" in tribute to Bolt.
The three-year-old thoroughbred - and favourite, made a disappointing appearance at Sandown Park on Wednesday, only managing fifth.