Goaltending is a ridiculously fickle, unpredictable position. Goalies can go hot and cold at a moment's notice. They're sort of like field goal kickers. That's why tying up goaltenders in long-term, high cap hit contracts is generally a poor investment, and also why drafting goalies in the first round is a bad idea.
Right now, the Flyers have two goalies who are in stone cold slumps at the same time, just as they both were hot for much of last season.
A shakeup might not be a bad idea. I wonder if you could trade Mason to Arizona for Martin Hanzal, and call up Stolarz?