You have to be careful when you listen to Danny. Yeah, he says Allen is a good player, and he says he thinks he'll be able to contribute for another four years. But he also says Ray understands that it's a business and that anyone can be traded. In other words, he's not giving any real information.
In my opinion, Danny is talking around (like any GM does), and if he finds a deal strongly in the Celtics favor, he's going to pull the trigger.