McCourty was taken out of last week's game with a bad case of "friendly-fire" and needed a few days off to heal up his shoulder. As soon as he went down, the first thought was "Dislocated Shoulder", but the injury was slightly greater. If McCourty is already back at practice (albeit limited), then it shows that the injury was minor and that he could have used a couple days off to rest up a sore shoulder.
However, don't expect McCourty to take the field against the Chiefs. The Patriots have been using this week as a mini-Bye week by limiting the majority of players who have sustained injuries at any point this season. Giving these players time off and allowing them to heal up is a huge benefit as the team hits their final stretch of the season.
McCourty's return most likely holds the same weight as Jerod Mayo's premature return from his early season injury. Getting McCourty back on the field as soon as possible and not allowing him to miss a beat is imperative for McCourty to re-find his groove. Look for McCourty to take the field against the Eagles.
Of course, if I were the coach, I would have saved the mini-Bye for the Colts week, but with an extra day of rest this week, I can understand the decision.