I think they know that they're about to make a move and they don't want to waste an option. What's very interesting is that the deadline isn't until Sunday, and you know that they won't go more than 1-2 days with a 24 man roster, so something has to be right on the fringe right now. The more I think about it, the more I expect something to happen by tonight.
Then again, they could be waiting to see if something that is in the works right now pans out, and if it doesn't, they could call up an OF from AAA today or tomorrow.