"If I felt that I didn't deserve to be included, I would be able to live with and accept the decision, but that isn't the case," Donovan told reporters.
"If you need to judge it by events on the pitch, I think I don't just deserve to be called-up, I think I deserve to go to the World Cup. Not just for what I have done in the past, but because of how I worked during the last two weeks.
"I am disappointed and upset. I am human and I want to play in the World Cup, but I am calm and I respect the decision. I believe I deserved to be included, this is a bitter pill to swallow."
Donovan has made 154 appearances for the USA national side, scoring 57 goals.