Nearly every NHL team, including the Boston Bruins, is set up the same way as has been for years: four lines of forwards, three defense pairs, two power play units, and two penalty kill units. A team’s top-six forwards are who they depend on to score the goals and the third line plays a combo role of depth scoring and defense.
But that fourth line? They’re supposed to be grinders; the players you can throw out to frustrate the top lines of the opponents. Typically, what they lack in “skill”, they make up for in scrappiness and physicality.