Being a part of something and contributing your talents. He was being used - significantly. If he was getting exactly what he wanted then someone else is in the same boat he currently sees himself in - which he’s fine with, as long as it’s not him.
The whole problem with this is the fact he was on the field, contributing, not riding pine and it’s not good enough. There’s no place for that. I would have discussed his selfish attitude to make sure we understood each other and if he still wanted to leave - I’d have helped him pack to get him out of my site as fast as possible. You don’t leave in the middle of the battle, when your TEAM doesn’t have the time to really adjust like in the off season. If he only had one season left there’s an outside chance of understanding - this is crap!