A guy I work with on the weekends is a teacher at SJU. He seemed pretty confident that Harrison has every intention of coming back next season. He did add however, that it isn't Harrison's decision. It's Lavin's.
Like everyone else has said, it wasn't one particular incident, rather a long history of bad behavior and disrespect. He hadn't heard of the supposed altercation with Hines while Lavin was away.
Basically he said Harrison thinks he plays by a different set of rules and completely disrespects the entire staff . I mean, do you really tell Keady to go F off? We shall see what happens.