Todd Walker's injury, following a collision with Carlos Lee today, is initially being called a left knee sprain, according to MLB.com. He underwent an MRI, and the Cubs are awaiting the results.

My wife, who is a physical therapist, had the initial reaction of it's a torn MCL. Let's hope that turns out wrong. Otherwise, we're about to be left hoping that Jerry Hairston, Jr. can duplicate last year's .378 OBA, which he posted in part-time play.

UPDATE: Unfortunately, my wife was correct. The Cubs announced today that Walker has been placed on the 15-day DL "with a moderate to severe medial collateral ligament sprain of the left knee." A moderate to severe MCL sprain is at least a partial tear of the MCL.

The Cubs called up infielder Mike Fontenot, received from Baltimore in the Sammy Sosa trade, to replace Walker. Fontenot hit .279/.346/.420 in Triple-A last year and had an 845 OPS in 30 at-bats for Baltimore. With Richard Lewis playing second base at Iowa, Fontenot was playing third base.

My initial reaction was that it was strange that the Cubs didn't call up an outfielder, given that Jerry Hairston, Jr. will now become the starting second baseman and be unavailable to backup in the outfield. But there's the small problem of their being no other outfielders on the 40-man roster. Jose Macias can also play the outfield.

UPDATE II: Trainer Mark O'Neal says 4-6 weeks recovery time, though that's just speculation at this point. Also, Walker doesn't consider Lee's slide malicious. He did offer this funny statement after seeing the photo of the slide: "It looks like he's doing some kind of tae kwon do on my knee."