That is the sound you hear off in the distance today. Cardinal fans laughing. While it's not yet known how long the Cubs might be without Derrek Lee, it's almost certain that Prior is out for an extended period of time.
Prior is in L.A. for an MRI to get his sore shoulder looked at. But even if it is merely soreness, he has yet to throw in a game this spring. If the Cubs were being careful before I can only guess Prior will be taking the mound in armor and a sealproof bubble upon his return.
So with his spring likely over he would need to go to the minors for some work before he is ready to pitch in the bigs. And that's assuming that he is diagnosed with just soreness and no internal damage. I don't see how he could pitch before May in a best case scenario.
If you consider that Wood and Prior will miss time and now Lee is banged up, the Cardinals might as well take the first 60 games off. They likely have the division in hand and it's not even April yet.