Ash, I believe that it was reported by Jeff Howe (could've been someone else) that Dobson has felt healthy enough to practice and play for a little while now, but the coaching staff has held him out anyway for his sake. Jeff (or whoever) speculated that this is the way the team would treat a "lock" player - if he was on the roster bubble, they would be putting him out there to see what they've got. No sense in holding back a guy you don't even know if you're keeping.