Gay qualified in the 100m and 200m at the nationals in June, but relinquished his spots after failing an out-of-competition drug test for a banned substance. Mike Rodgers will take Gay's place in the 100m and Wallace Spearmon will go in the 200m.
The team was announced on Monday by USA Track and Field.
Carmelita Jeter will run the 100m and be among several Americans trying to defend their world titles, beginning August 10. The US team also includes up-and-comers such as 17-year-old Mary Cain in the 1 500m.
Finally healthy this season, Gay was expected to push Usain Bolt at the worlds. But instead of racing in Russia, Gay will be trying to resolve his doping case.