Olazabal announced his two wild card picks yesterday, with no place for the three-time major winner.
Instead, Ian Poulter and in-form Nicholas Colsaerts were added to the 10 automatic qualifiers.
"Even the dogs in the street knew I wasn't getting a pick," said Harrington. "It wasn't a tough phone call for me to take whatsoever.
"If you don't make the team automatically, you can't have any regrets. You can't second-guess getting a pick if you don't make it on merit."
Harrington fell out with Olazabal in 2003 and it had been suggested that it could harm his chances, but the Irishman insists there are no hard feelings.
He continued: "It was a polite call from Jose. What he had to say wasn't news to me and I was comfortable with his picks. Ian and Nicholas were very obvious selections, so there are no questions or issues with that."
The Ryder Cup gets underway at the Medinah Club in Illinois on September 28.