He had the guillotine over his neck for about three months now. The team got off to their real fast start, but the front office didn't extend his contract for 2006. That pretty much told everyone in Baltimore that Maz wasn't likely to be brought back (unless the team actually won the division or the wild card). As the team slipped further and further it became a matter of time (there were a few columns in recent days in the Baltimore Sun speculating about his future).
Anyway, I think this is bad for my beloved O's. It's going to be another situation where the organization is starting from scratch with its off the field personnel (the GMs aren't signed beyond this season, and I'd imagine the coaching staff will be gutted). I never liked Mazzilli as a tactical manager (in fact I often thought that he suffered from acute brain death), but it seemed like he still had the confidence of the team. Now they've given up on the season, and the team can embark on its next plan of action. Yippee. What an owner this team had.
Maybe he wasn't happy with how he handled the staff? For me, at least (and why I disagree with Beane on this count), the catchers' primary role is make sure that the pitchers pitch the best they can on any given day.