Pittsburgh Penguins defenseman Justin Schultz has been the lone spark plug on the team's blue line, but he's been playing hurt and that's a big problem if the reigning Stanley Cup champions want to repeat.

Schultz suffered an upper-body injury early in Game 2 of the Eastern Conference Final against the Ottawa Senators. He only played 3:40 in that contest, and went on to miss Games 3, 4, 5, and 6 before returning to action in Game 7.

Having Schultz back in the lineup for Game 7 is a major reason why the Pens came out victorious, as he recorded a goal and an assist in the do-or-die game. Even though Pittsburgh got dominated in Game 1 of the Stanley Cup Final against the Nashville Predators, he played a big part in its win, assisting on Jake Guentzel's game-winning goal.

Despite his return these past two games, it's clear that Schultz isn't playing at even close to 100 percent health. Otherwise, he would be getting more ice time. Take a look:

He's seen the fewest minutes of any Penguins defenseman since returning to the lineup, clearly indicating that he isn't quite right. He saw more minutes than any Pens blue-liner in two of the three games prior to his injury.

The Penguins were able to mitigate Schultz's absence in the Eastern Conference Final because the Senators sit back and play the 1-3-1, and they don't bring a heavy forecheck like the Predators do.

Schultz's best qualities as a defenseman are his skating, passing, and ability to move to the puck out of his own zone. The last part is key, because without Kris Letang in the lineup, Schultz is Pittsburgh's only above-average puck-mover on the back end.

Dmitri Filipovic of Sportsnet tallied the following information from Game 1:

As you can see, aside from Schultz, the Penguins' defense had no problems simply getting the puck out of the zone, but rarely did Pittsburgh posses the puck once it was outside the blue line. That's because these five D-men are all defensive-minded, and don't have the ability to make crisp breakout passes with forecheckers breathing down their neck.

Here's an example of Hainsey making a poor decision as the last man back:

Some may be puzzled how a team with Sidney Crosby, Evgeni Malkin, and Phil Kessel managed to go 37 minutes without a shot on goal, and record just 12 total in the game, but here's your answer: When Schultz isn't on the ice, these elite forwards have nobody to get them the puck.

To be frank, Pittsburgh was very lucky to come away with a victory in Game 1. Sure, having Schultz play 16 minutes is better than him not playing at all, but the fact that Mike Sullivan can't put him on the ice willy-nilly could eventually lead to the demise of the Penguins in this series.

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