With apologies to Trinidadians Richard Thompson and Keston Bledman, who could conceivably reach the podium, we take a closer look at these eight sprinters, whose names are preceded by their time in seconds in Saturday's opening round heat.
9.88: Ryan Bailey, United States
The American is a bit like Usain Bolt and Yohan Blake, albeit without a single one of their accomplishments. What that means is he's one of the younger medal contenders like Blake — both were born in 1989 — and he is six-foot-four, making him one of the few sprinters who doesn't have to crane to look up to Bolt.
Bailey's just happy to be in London, but in the most positive way: As a teen he knew poverty first hand and survived a stabbing.
He matched a personal best with his first round time on Saturday. Was it a sign of things to come, or the time of someone so eager to prove himself that he doesn't leave enough mystery for the semis and — he hopes — the final?
9.97: Justin Gatlin, United States
Gatlin is trying to do something unprecedented by reaching the podium in the event eight years apart. He won gold in Athens by running a personal best 9.85. It appeared he had tied Asafa Powell's then world record of 9.77 in 2006, but it was ultimately taken away when Gatlin was suspended for four years for elevated testosterone levels, one of several athletes under notorious coach Trevor Graham who were rounded up.
After a period in the wilderness that included unsuccessfully trying out for the NFL, Gatlin was able to compete again in 2010. He has pronounced himself humbled by the imposed ban, while maintaining that he never knowingly took a banned substance. He bowed out in the semis at the worlds last year, but served notice that he was back in form this year with impressive runs in Doha and at the U.S. Trials (a personal best 9.80).
10.00: Yohan Blake, Jamaica
The man who would be king?
Blake can signal a passing of the torch and cap off a tremendous 12 month period with a victory on Sunday.
Blake this summer joined countrymen Bolt and Asafa Powell, and American Tyson Gay, as the only men ever to clock 9.75 or under. He ran 9.75 to topple Bolt at the Jamaican Trials, and he beat his training mate in the 200 as well.
He first stole the spotlight from the global superstar Bolt at last year's world championships in South Korea. When Bolt was disqualified due to track's dreaded false start rule, Blake crossed first for gold in a time of 9.82, which matched personal best at the time.
He has not escaped suspicion in his career, with a disputed reading in 2009 of the stimulant MHA.
10.02: Dwain Chambers, Great Britain
The 34-year-old Briton would be one of the more improbable podium finishers of all-time in the 100 should he finish in the Top 3.
After finishing fourth in the 100 at the Sydney Games, he received a lifetime ban from most major competitions after testing positive for the steroid THG, part of the BALCO scandal. He did Gatlin better in the fallow years, which lasted about half a decade. There were dalliances in both American football and rugby, along with publishing an autobiography and appearing on reality shows.
His best results since a lengthy but successful appeals process have come indoors, and he false-started out of the outdoor world championships in Daegu last year in the semifinals.
10.04: Asafa Powell, Jamaica
Powell perhaps epitomizes the vagaries of the 100 more than anyone else. No one in history has gone under 10 seconds as many times, but he's also never won individual gold at either the Olympics or world championships in either the 100 or 200. He finished fifth at the shorter distance at both the Athens Games and in Beijing.
Usually a terrific starter, he's admitted that the battle has often been in his head prior to the gun. He held the world record for about three years, lowering it to 9.72 until Bolt took over in May 2008 with his time at Randall's Island in New York City.
Powell's best time in recent years is a 9.87 in Lausanne. He has been a little closer to victory against his main rivals this season than in recent years, losing narrowly to Bolt and Gatlin in separate races.
10.08: Tyson Gay, United States
Gay won three gold medals at the 2007 worlds in Tokyo, beating Bolt in the 200. He has the run the fastest time ever clocked by a guy not named Bolt, the 9.69 he put down in Shanghai in 2009.
He also beat Bolt in a 100 in 2010, but acknowledged that the Jamaican was on the mend. If anyone knows about the importance of health, it's the humble Kentuckian, who has been dogged by hip joint and hamstring injuries. One couldn't help notice Gay walking gingerly after his impressive first heat on Saturday.
Gay ran 10 flat in his opening race at the U.S. Trials last month, an extremely impressive time for someone who hadn't been in a competitive race in about a year. He was 9.86 in the trials final, second only to Gatlin.
10.09: Justyn Warner, Canada
How many times can a guy set a personal best?
For Warner of Markham, Ont., it will have to be three to even be in shouting distance of the podium, as the 10.09 from Saturday was the best he's done.
Unfortunately, each of the seven other entrants in his semifinal has run faster at least once in their career, led by Blake and Gay.
10.09: Usain Bolt, Jamaica
Has the sleeping giant been roused into approaching world record form again? Bolt can become the first man since Carl Lewis in 1988 to win consecutive gold medals in the 100, and Lewis was deprived the pleasure of actually crossing the line first, handed the gold after Canadian Ben Johnson tested positive for steroids.
Bolt came into the 2008 Games having set a new world mark of 9.72. He won in Beijing in 9.69 despite cruising the last few metres, and ran an eye-popping 9.58 at the Berlin worlds a year later for a standard that has yet to be matched.
Since then there's been victories, worrisome car crashes and a disqualification in the Daegu final last year due to the sport's controversial false start rule. The last incident weighed on him, and Bolt admitted that he was gun shy in subsequent races. But not now, he says.
Still, the gap has been narrowed and even bridged this year without the aid of a DQ. He ran an impressive 9.79 in June in Oslo, but Powell wasn't that far behind. It seemed Bolt was on the right path, but Blake usurped him in the 100 and 200 at their country's trials.
Bolt then pulled out of a scheduled race in July.
Whether it was a worrisome indicator of health or a smart move to rest and recuperate remains to be seen.