This is why I love the Captain. He knows his legacy as a Celtic is sealed forever and he knows if his being traded or coming off the books makes the team better, then the team has to do it and he's professional enough to understand. He's making it clear that his heart is in remaining a Celtic and will end his career a Celtic, but if making the Celtics better means he has to go, he okay with that.
Besides, the Truth knows it will probably make being a part of a championship team again for Pierce a real possibility, which I am sure would be alright with Mr. Pierce.