What's wrong with Sidney Crosby?

OTTAWA -- On some level, Sidney Crosby understood the challenges that come with trying to captain a team to a second consecutive Stanley Cup. Having already gone through it once, he grasped that his team would need luck. The Pittsburgh Penguins would need bounces. They'd have to have a singular game-by-game focus, something this group does exceedingly well.
Still, even in understanding all of that, the reality is setting in as to just how hard it is to pull off a championship run in back-to-back years, with his banged-up team now down 2-1 in the Eastern Conference finals heading into Friday's Game 4 against the Ottawa Senators.
"Yeah, absolutely," Crosby said. "Definitely a greater appreciation for it now."
Aside from the luck and the bounces and all the things that influence a hockey game outside of skill, determination and timely saves, the grind appears to be dangerously close to catching up to Crosby and his Penguins.
The news conferences of Penguins coach Mike Sullivan have turned into triage reports, with new names added daily to the injury list. As the depth scoring and defensive health have disintegrated, more of the burden has fallen onto stars Crosby, Evgeni Malkin and Phil Kessel to generate the offense on their own.
Each has taken turns scoring in this series but not frequently enough to keep up with the more balanced (and healthy) Senators attack in this series, where they've been outscored 7-2.
Crosby's goal in Wednesday's 5-1 loss was his first since scoring twice in Game 1 against the Washington Capitals on April 27. He hasn't scored an even-strength goal since returning from the concussion suffered in Game 3 against the Capitals. He's a minus-4 so far against the Senators, just one round after finishing a plus-4 against the Capitals.
Those in the game have a couple of theories as to why it has become much harder for Crosby to score as these playoffs have progressed.
The first is that a banged-up Penguins defense has cut down on offense Crosby and his line can produce in transition. The odd-man rushes that were there earlier just haven't existed against the Senators and really didn't exist as the series against the Capitals progressed.
"When you don't have your top defensemen [and instead] guys like Chad Ruhwedel and Ian Cole, they're not creating turnovers," an Eastern Conference scout said. "They're more worried about, 'Let's not get scored on.' "
That combined with the fact the Senators play a system that just isn't going to allow too much offense on the rush means Crosby and his linemates will have to generate in other areas at even strength.
"He will have to do it from the corners instead of the rush because Ottawa doesn't give you a rush game," one assistant coach said via text.
The other challenge heading into Game 4 is that Crosby probably will see another steady dose of standout defenseman Erik Karlsson because Senators coach Guy Boucher has more control over matchups at home. Plus, Karlsson plays half the game.