Crosby's preference isn't the only reason, though. At any given moment, Kunitz could come through in a big way, as he did with two goals in a 3-2 double overtime win against the Ottawa Senators in Game 7 of the Eastern Conference Final.
Kunitz could have one last surprise against the Nashville Predators in the Stanley Cup Final, which begins with Game 1 at PPG Paints Arena on Monday (8 p.m. ET; NBC, CBC, SN, TVA Sports).
"You never know if you're going to play on this ice again with this team," Kunitz said. "So, you've got to make sure you make that last as long as you can."
Kunitz's numbers have fallen off considerably over the past three seasons.
After scoring 35 goals in 2013-14, he had 17 in the following two. This season, he scored nine goals, the fewest since he failed to score in 21 games as a rookie in 2003-04.
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After 13 NHL seasons, Kunitz, 37, is more than a step slower. Sometimes he struggles to keep up in a lineup structured around speed. Still, Crosby enjoys playing next to Kunitz, whose grit is welcome on the top line.
The first line needs more than grit, however. Kunitz wouldn't be put in that position if Crosby and Penguins coach Mike Sullivan thought he couldn't produce.
"I think he's got that knack for being a big-game player," Crosby said. "He does so many little things. Probably a lot of things go unnoticed."
Before Game 7 of the conference final, Kunitz hadn't scored since Feb. 16. That changed after he and forward Conor Sheary were elevated to Crosby's line in the second period.