Just to keep the discussion going, the stories are out and it's pretty much what Buster Olney said earlier. Beane felt like there was a roster crunch coming and that Bradley wasn't going to deal with being on the bench or being a part-time player. At least that's the story he's giving.
You know, the truth is that there is probably more to this than we'll ever know. But I do think that getting rid of Bradley now does help you get a better sense of what the outfield will be in 2008 (Bradley clearly wasn't a part of that plan) and it wasn't like Bradley had proven that he could stay on the field for more than seven games at a time. This gives the A's to give players that Beane has loved for a long time like Cust and Snelling a chance to prove if one of them can be a regular contributor.
Do I think that was the main reason for the move? Probably not, but unfortunately, the ending of this Bradley saga is as open to interpretation as the ending to The Sopranos.