You'll notice that Jaime Castrillon, Colorado's leading scorer last season, has been absent from just about everything this preseason. It came out a while ago that he was suffering from a knee injury dating back to last year, which had kept him off the field. Unfortunately, according to the Denver Post's Terrace Blog, it's even worse than that -- Castrillon is going to need knee surgery that could keep him out for several weeks.
This probably isn't going to help the case to keep him around in Colorado for next season. Rumors started up a while ago saying that a move back to his native Colombia was possible, joining other MLS Colombian players like Fredy Montero who have started to move back to their rejuvenated home league.
I guess we'll see when more details come out about the surgery. Either way, it doesn't look like Castrillon will be seeing the field for quite a while.
Fun fact: this means that the Rapids will be starting next year without the ability to play their leading scorer from every single season between 2009 and 2012, all of whom were either off-loaded or injured seriously this off-season. (Conor Casey, Omar Cummings, Jeff Larentowicz, Castrillon.)