Penguins find balance with Erik Karlsson-Matt Grzelcyk defensive pairing

From left, Matt Grzelcyk, Erik Karlsson and Sidney Crosby celebrate Karlsson’s goal with Rickard Rakell against the Carolina Hurricanes on Jan. 5.

Back in mid-December, Marcus Pettersson landing on injured reserve forced the Pittsburgh Penguins to do some tinkering on the blue line.