The Washington Capitals led the Philadelphia Flyers 2-1 on Saturday when the Caps’ Nicklas Backstrom, on a power play, collected the puck near the right corner. He turned and zipped a pass through the legs of his teammate, T.J. Oshie, across the ice to Alex Ovechkin, who was waiting with his stick up and loaded. Flyers goalie Steve Mason dropped to his knees, slid to his right and watched helplessly as Ovechkin timed the pass and smashed it into the net in one devastating motion.

In today’s NHL, where the goalies are limber,...