Tatum suffered a career threatening injury and Brown calls it his favorite season. I don't know if this was a direct shot, but I can't blame Tatum if it was.
Maybe Tatum had a hand in getting Brown moved, but more likely, I don't think Stevens thought those two could work together again after Brown got a taste of being the #1. And if that contract extension wasn't offered, there was a real possibility of things going sour quickly. The team won a championship, but it's likely with salary constraints, Stevens thought that those two making 70% of the cap weren't getting there again.