Mark Prior has left the game tonight during the second inning, apparently tweaking his achilles. Rusch has taken over.

We'll learn (much) more about the extent of this injury in the near future, though the Tribune has initially characterized it as more precautionary than anything else: "[Prior] broke off the mound on a ground ball to first and the Cubs training staff and pitching coach Larry Rothschild decided to play it safe."

Let's hope "play it safe" is the extent of it.

Update 9:30 PM ET: While there still is no official word, the Brewers broadcasters are saying Prior left due to some "tenderness" in his right elbow. There clearly isn't a whole lot of information available yet.

Update 11:50 PM ET: Confirmation that it was his right elbow that was tender.