Thanks for your responses. I wanted to place the situation to a league vote, which I thought would be the most logical thing to do. Personally, I didn't mind the guy changing keepers even if the principle of a deadline is violated. Only myself and one other manager voiced opinions.
But now the commissioner has reversed his decision because of our questions and ideas. And the manager in question now seems to like having Wainwright as a "chip on his shoulder" so if he beats everyone, he can say he did it handicapped.
Thanks again for your responses. The lesson learned, I suppose, is to involve your league in decisions and keep communication lines open.