The roster is missing most of the national team's regular starters, such as Clint Dempsey and Tim Howard, who will be on summer vacation before returning to their European clubs for the 2013-14 season.
Some of the players are currently with the U.S. team, which is preparing for three World Cup qualifiers in June. U.S. coach Jurgen Klinsmann omitted Donovan, who is playing his way into shape with the Los Angeles Galaxy following a four-month sabbatical, from his current camp along with Bocanegra, who lost his starting job with Racing Santander of Spain's second division and regained it in April.
Rosters must be trimmed to 23 by June 27, but the 12 players dropped can be added to the active roster after the group stage.
The Americans open against Belize at Portland, Ore., on July 9, play Cuba at Salt Lake City four days later and close the first round against Costa Rica at East Hartford, Conn., on July 16.
The winners of the 2013 and 2015 Gold Cups will meet in a playoff for a berth in the 2017 Confederations Cup.
The full preliminary roster:
Defenders: Corey Ashe (Houston Dynamo), DaMarcus Beasley (Puebla), Tony Beltran (Real Salt Lake), Matt Besler (Sporting KC), Carlos Bocanegra (Racing Santander), Edgar Castillo (Tijuana), Omar Gonzalez (LA Galaxy), Clarence Goodson (Brondby), Oguchi Onyewu (Malaga), Michael Orozco (Puebla), Michael Parkhurst (Ausburg)
Midfielders: Kyle Beckerman (Real Salt Lake), Alejandro Bedoya (Heisingborgs), Joe Corona (Tijuana), Brad Davis (Houston Dynamo), Mix Diskerud (Rosenborg), Landon Donovan (LA Galaxy), Brad Evans (Seattle Sounders), Benny Feilhaber (Sporting KC), Josh Gatt (Molde), Stuart Holden (Bolton), Brek Shea (Stoke City), Jose Torres (Tigres), Graham Zusi (Sporting KC)
Forwards: Will Bruin (Houston Dynamo), Herculez Gomez (Santos), Alan Gordon (San Jose Earthquakes), Eddie Johnson (Seattle Sounders), Jack McInerney (Philadelphia Union), Chris Wondolowski (San Jose Earthquakes), Bobby Wood (1860 Munich)