The 23-year-old Jamaican has been bothered by a sore hamstring since April when he competed in the Utech Classic in Jamaica.
"The injury sustained in April of this year has prevented him from attaining the necessary fitness levels that we have grown accustomed to seeing in his performances," Blake's agent Cubie Seegobin said.
The injury also forced him to miss last month's Jamaican trials.
Blake's withdrawal not only robs the event of its defending sprint champ but it adds to the list of marquee performers who have been ruled out of the event, including some for failing doping tests.
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Blake has a personal best of the 9.69 seconds in the 100m making him the co-second fastest man ever behind Jamaican teammate Usain Bolt. Gay has also run a 9.69.
Blake finished second in the 2011 Daegu World Championships but was awarded the gold after organizers disqualified Bolt.
Defending champ Bolt was disqualified after he jumped out of the blocks too early.
Blake capoted two silvers in his first Olympics at the 2012 London Games in the 100m and 200m. He won gold in the 4x100m relay.
That came 11 months after he ran a personal best of 19.26 in the 200m at a meet in Brussels, Belgium.