Yeah, dislocation was obviously silly. But, while it is possible that the benching had to do with him being banged up, it seems like the strong conviction with which L.M. implied that was the case might have been wishful thinking.
I also feel like if the injury was associated with the benching, the coach/someone might have pointed that out. Maybe it's just me, but I know if I was the coach and I benched one of my players who was injured after he struggled, I'd point out that he tried to play through an injury but wasn't able to move quickly enough to defend, and so I insulated him moving forward. Especially if I was coaching Jr. level players in a short, high-stakes, high-visibility tournament like the WJHC.