Grabban had agitated for a move to Bournemouth during the summer and petulantly displayed his disapproval when he did not get the switch by failing to suit up for a Capital One Cup clash against Rotherham earlier in the season.
Grabban eventually earned a move to Bournemouth after joining in a £8million deal this week and Canaries boss Neil was satisfied to have offloaded the 28-year-old.
Neil said: "We just felt he was a player who had run his course at Norwich. He was not involved, he was not in our squads.
"Lewis contributed greatly to us getting promoted and started the season for us, then we had a couple of incidents afterwards, and to be honest I don't think we really recovered from that.
"I think it was one of those where Lewis had come to the conclusion that he was best suited to playing elsewhere, and we agreed with that. Sometimes players have their heads turned and get their heart set on going elsewhere."