They'd already ordered all 22 episodes, so I don't think they would have canceled mid season. Its an obvious move, tbh, given x facotor coming online soon and Thursdays being a tough night. There really isnt anywhere else to go except Fridays, but I'll be surprised if it pulls the necessary numbers to get a season 4. Sad part is, Fring gets something like a 40% bump in DVR numbers which won't change with the move to Fridays, but thise numbers don't matter for profitability.

If it does pull it off, it'll be pretty awesome. 'x-files' lived on Fridays for quite a while. Science fiction geeks may be the most likely ones to stay in on a Friday night