Donovan said this week his knee was OK.
"I'm very confident in my abilities and I'm deserving to be a part of the squad, but I have to prove that, and I have to earn it," he said on Monday.
Just six players return from the 2010 team: goalkeepers Tim Howard and Brad Guzan; midfielder Michael Bradley; forwards Jozy Altidore and Clint Dempsey; and defender DaMarcus Beasley, who is bidding to become the first American to play in his fourth World Cup.
Beasley and Donovan were teammates on the U.S. team that finished fourth in the 1999 FIFA Under-17 World Championship.
"Landon is my brother. I've known Landon since I was 15. We've been through a lot together," Beasley said. "To not have him there is difficult."
Goalkeepers: Brad Guzan (Aston Villa), Tim Howard (Everton), Nick Rimando (Salt Lake)
Defenders: DaMarcus Beasley (Puebla), Matt Besler (Kansas City), John Brooks (Hertha Berlin), Geoff Cameron (Stoke), Timmy Chandler (Nuremberg), Omar Gonzalez (Los Angeles), Fabian Johnson (Borussia Moenchengladbach), DeAndre Yedlin (Seattle)
Midfielders: Kyle Beckerman (Salt Lake), Alejandro Bedoya (Nantes), Michael Bradley (Toronto), Brad Davis (Houston), Mix Diskerud (Rosenborg), Julian Green (Bayern Munich), Jermaine Jones (Besiktas), Graham Zusi (Kansas City)
Fowards: Jozy Altidore (Sunderland), Clint Dempsey (Seattle), Aron Johannsson (AZ Alkmaar), Chris Wondolowski (San Jose)