Keane claimed he left Sunderland because majority shareholder Short began meddling in "team affairs".
He said: "One of the big conditions I had when I went to Sunderland was that there would be no interference with team affairs.
"When someone tries to move the goalposts, it has nothing to do with contracts, it is about a promise with people at the club. You have to be relaxed and have trust in the people you are working with. I told them 5,000 times not to interfere."