How is Sheahan's face off percentage and penalty killing?
Faceoff percentage has been excellent, PKing has been solid. He's over 55% on faceoffs.
Does he shadow top lines or is he a good lock down guy?
He has a defensive zone start% of 65% against pretty high end competition. He also hasn't gotten scored on much and has some great defensive advanced stats (like corsi against).
He's a pretty good skater, not a burner but he gets around nicely. Better skater than Bonino IMO. He doesn't throw around his body too much, but he has gotten into the dirty areas a good amount. He's physical the same way Crosby is physical, he gets engaged in the dirty areas and plays the cycle game, but he's not throwing his weight around.
Not a requirement of a 3C.
Does he show any desperation? Any Leadership?
We have no way of knowing about leadership since we're not in the locker room. I hate when people try to evaluate the mental or social aspects of players. No one here has any idea about that, so to even bring it up is flawed.
What does he do that I am missing.
Well a lot, because of the questions you're asking. The only thing he doesn't do at a 3C level is scoring goals. Here's what he has done so far:
1. Showed he can play extremely heavy defensive minutes, seeing how he starts 65% of his shifts in the Dzone. That's higher than what Bonino did here.
2. Showed he can have solid possession stats in those heavy defensive minutes. For someone with Sheahan's assignments, his possession stats are really good. Having a CF%REL of close to 0 and a positive CF% when you're getting those Dzone assignments is legitimately impressive. CF%Rel is just how your CF% compares to the rest of your team, but it doesn't take into account zone starts or any other context with that. It is legitimately impressive that his CF%Rel is at 0, which means his CF% is just as good as the average on the Penguins, because of the difficult minutes he's getting.
3. He has shown good playmaking abilities for a 3C. He's on pace for 22 assists per 82 games so far in Pittsburgh from the 3C spot, that's a solid number and all were either primary assists or secondary assists where he played a huge role in the play.
4. He has shown he's excellent on faceoffs and can kill penalties well.
He's getting hammered with DZone minutes and performing very well in that role. Yeah, I wish he would score a couple more goals. That's really my only complaint when it comes to him. Playmaking, defensive play, faceoffs, possession stats, minutes played, zone starts...they're all clearly 3C caliber.
If Sheahan manages to rediscover his goal scoring game and he continues to do what he has done in Pittsburgh, he is flat out indisputably a 3rd line center. Probably a good one, too. Not one that can reliably step up into the 2C spot, but a good 3rd line center. That's just a huge if, and until he does that, he's a mediocre 3C at best. I don't care how well you do everything else, you're not going to be higher than a below average 3C if you can't score goals.