McKennie separated his shoulder in training

McKennie has shoulder instability, which is common when you dislocate the shoulder and have a large enough labral tear. The damaged labrum fails to stabilize the humerus in the glenoid, and some people with this issue can dislocate even from rolling in bed wrong. He last dislocated it while playing for Schalke I believe.

Does this need surgery? Maybe. Does he need it right now? No.

Surgery for this sort of thing is an individual, case by case decision. As a high level athlete he should probably have the surgery done at some point, but it can wait until after the season is over. For now he can probably rehab it, make sure it’s strong, and come back in a few weeks. If we had a World Cup game to play in the next few days he could probably play.