The blade in starting goaltender Sean Maguire’s skate had popped out, and in what seemed like a split second, Connor LaCouvee was ready to go. His mask was on, and he stretched, quickly warmed up...

  He puts on the scarlet and white sweater, laces up his skates and joins his teammates in a single-file line into the tunnel that connects the bowels of Agganis Arena to the playing surface. After...