Torey Krug is the Bruins’ power-play quarterback. There are few in the NHL who can rival Krug’s work.



But there are times when Krug freelances. On occasion, Krug initiates the delay to enter the offensive zone, a move outside of the guidelines he received earlier that day.



That’s when Bruce Cassidy loses it.



Cassidy oversees the power play. It is a part of the game the Bruins coach, an offensive defenseman in his day, especially enjoys.



Through his research, Cassidy has concluded that for the No. 1 power-play unit, a speed entry — in-stride carries on the flanks by Brad Marchand and David Pastrnak or up the middle by Krug himself — is the most efficient method to cross the offensive blue line.



So when Krug drops a mid-ice puck for one of his trailing teammates to receive on the delay, Cassidy cannot help but roll his eyes. When this happens, Cassidy sometimes turns to assistant coach Jay Pandolfo, who helps on...