Donovan, the U.S's all-time top scorer, was missing from the list of 26 players announced by head coach Juergen Klinsmann on Thursday.
The 31-year-old missed the team's earlier qualifiers this year after taking a self-imposed break from the game.
Donovan resumed playing for his MLS club L.A. Galaxy in late March but his performances did not impress Klinsmann enough to earn a place in the squad.
"I'm disappointed that I'm not (selected) but I'll keep going and I'll keep working hard and I hope that I get the chance," Donovan told Reuters in an interview on Thursday during his campaign with The Skin Cancer Foundation to promote awareness of the disease..
"But I certainly understand it, I've been gone for a long time. I basically excused myself from the first three so I understand the way the world works," he said, speaking
"I would love to be in Brazil next year but I can't completely control that my job is to make it as difficult as possible for the coach to leave me out."
Donovan's omission from the squad for friendlies against Belgium and Germany and three June World Cup qualifiers, against Jamaica, Panama and Honduras, was largely expected.
Klinsmann said he was glad to see Donovan back on the field but wanted to see more progress from the winger, who has played in the last three World Cup finals.
"I think Landon is catching up. We're all excited that he has decided to continue to play. That was the first major answer that we needed to get, and now he's just working himself back into shape and back into a playing rhythm," said Klinsmann.
"He will get sharper and more confident with every game he's going to play now. So we'll watch that, we'll monitor that and we'll decide then when to bring him back into our picture. It's not going to be for these upcoming games, but maybe later on we'll definitely expect him back in the team."
The U.S. will name a separate squad for the CONCACAF Gold Cup tournament in July and Donovan said he would love to be a part of that team to try and get back in the full side for the further World Cup qualifiers in September and October.
"We have a very honest relationship," Donovan said.
"He's the coach and I think he's done a really good job with the team and it's my job now to get back in so I can be a part of this.
"My hope would be that I would get called into the Gold Cup squad. I sort of need to get back and prove myself there and prove that I can get back into the rhythm of the national team.
"I guess that will be in some ways a platform to get back into the fall side and hopefully eventually the World Cup."
Defenders: DaMarcus Beasley (Puebla), Matt Besler (Sporting Kansas City), Geoff Cameron (Stoke City), Edgar Castillo (Club Tijuana), Omar Gonzalez (LA Galaxy), Clarence Goodson (Brondby), Fabian Johnson (Hoffenheim), Michael Parkhurst (Augsburg)
Midfielders: Michael Bradley (Roma), Joe Corona (Club Tijuana), Brad Davis (Houston Dynamo), Maurice Edu (Bursaspor), Stuart Holden (Bolton), Jermaine Jones (Schalke), Sacha Kljestan (Anderlecht), Brek Shea (Stoke City), Danny Williams (Hoffenheim), Graham Zusi (Sporting Kansas City)
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