We're at the one-quarter mark of the season (a little over it, but close enough), and while that's not the best sample size to look at, it's at least enough to give us an idea of who's carrying their weight, who's not, and what we can expect going forward.
Overachieving:
Chris Kelly - Kelly is the early leader for the coveted Seventh Player award. Through 22 games, he has 9-7-16, putting him on pace for 34 goals. Barring injury, he should obliterate his career best offensive output of 15-23-38. Nothing about his quality of competition or quality of teammates stands out; he's in the middle of the pack for both. It's not like he's fattening up his goal scoring totals on poor opponents or that his linemates are carrying him on his back. So that suggests his hot start is fairly sustainable, right?
Well, not really. Kelly's shooting percentage is a blistering 22.5%. That's twice his career shooting percentage. We've got plenty of evidence to suggest that shooting percentage is a volatile thing, and a 22 game sample size tells us a lot less about Kelly's true abilities than the 486 games that preceded it. Kelly is 31 years old; it is highly unlikely that he has suddenly acquired the skills of a 30 goal scorer.
Kelly's having a remarkable season, and even when (not if) he cools off, he should still beat his career best offensive output. The best advice is to just enjoy it while it lasts, because at some point, he's going to go back to being what he truly is: a competent third line center who kills penalties and scores about once every 2 weeks.
Tim Thomas - In 2010-11, Tim Thomas had one of the best goaltending performances in history. He set a record for save percentage, won the Vezina Trophy, and carried a mediocre defense all the way to a Stanley Cup. A falloff was inevitable. At least, it seemed inevitable. Somehow, Thomas has been every bit as good, if not better, than he was last season. He has 3 shutouts so far, putting him on pace for 11; last year he had 9. He has a 1.86 GAA; last year he was at 2.00. His save percentage has declined, however...a whole one-thousandth of a point, from .938 to .937. At the most volatile position in hockey, Thomas has been a model of consistency; this is the third time in 4 years that his save percentage has been .933 or better.
Essentially, Thomas has been just as good as last year, but the Bruin defense has gotten significantly better. This year, they're surrendering 29.6 shots per game, down from 32.7. That's an enormous difference, and takes pressure off Boston's goaltenders. Unlike last year, Thomas has some room for error. For instance, if he just managed the .933 save percentage of his first Vezina Trophy campaign, and the defense continued to allow 29.6 shots per game, his GAA would still be under 2. And that's a good thing, because the volatility of the goaltending position, and Thomas' advanced age, means that eventually, his stratospheric save percentage is going to decline.
Underachieving:
David Krejci - Yikes. If it weren't for Milan Lucic, the first line would be a disaster right now. In 19 games, Krejci is a meager 3-7-10, with a -4 rating. Nathan Horton is a potential candidate for this list with an underwhelming 6-8-14 in 22 games, except that puts him on pace to do almost exactly what he did last season, so maybe it's time we accept that Horton is a good player who's never going to be a star.
Krejci, however, can be better, and he surely knows it. After his first round no-show, Krejci was easily Boston's best forward in the playoffs. In his age 22 season, he had 73 points. He can, and almost certainly will, play his way out of this slump. It's hard to imagine that the Bruins would contemplate a line switch; the HuLK line has enough work together to have established a good bit of chemistry, and breaking up the Marchand-Bergeron-Seguin line would be beyond ridiculous...almost as ridiculous as putting Chris Kelly in a first line role. No, Krejci is going to have to play his way out of this slump on the top line.
Benoit Pouliot - It's not that Pouliot has been terrible; he's a plus player, after all. But on a line where Chris Kelly and Rich Peverley are blazing away with 16 and 14 points each, respectively, you'd think that Pouliot would have picked up more than 3 points in 17 games. It didn't help that he seemed to do his best to throw a game to his old team in Montreal last week with a pair of penalties so dumb that I expected to find out that Philadelphia traded for him after the game. Some improved play of late, including a shootout winner against Buffalo and a strong game against Winnipeg, has probably lengthened his leash, but Jordan Caron is waiting in the wings, and Zach Hamill looked good enough in his brief call-up that maybe it's time to give him a look on the third line.
Achieving:
The Second Line - No, I don't think they're overachieving. Tyler Seguin's performance has been a revelation, but it seems clear that he just has a more rapid development curve than initially suspected. At the start of the season, I would have been content with 50 points from Seguin; now he looks like he has a real chance to be Boston's first 40 goal scorer since Glen Murray in 2002-3. Brad Marchand's speed and puck handling ability makes him a perfect fit on the opposite wing and he's showing that his rookie campaign was not a fluke. Patrice Bergeron has seemingly been lost in the excitement of the youngsters on his wing, but he's on pace for his best offensive season since before the Randy Jones hit nearly ended his career. Bergeron's defensive skill is invaluable to this line, as it allows the youngsters (Seguin in particular) to take some chances they might not otherwise take, knowing that Bergeron can help cover for their mistakes.
The Defense - I hate to lump everyone together here, because, as usual, Zdeno Chara is exceptional. Chara hasn't been good; he's been phenomenal. He has 16 points in 22 games, an off-the-charts Corsi rating, and does it all despite facing the best competition Boston's opponents have to offer. He stands a great chance at capturing his third...oh, right, last year he got robbed by a power play specialist with a minus rating...well, his second Norris Trophy.
Boston's game plan on defense is simple: have Chara and whatever lucky soul has been paired with him (this year, Johnny Boychuk) hold down the fort, and make sure the other 4 guys don't get killed. And the rest of the defense has more than held up their end of the bargain. Joe Corvo leads the team in power play assists and is tied for third in power play points. He has 9 assists overall and has managed to play fairly respectable defense. The Andrew Ference/Adam McQuaid pair has played significantly better as a pair than I expected, and Ference has shown quite an offensive streak with 7 points so far, including a game winner against Montreal, which is a feather in any Bruin's cap. His career high was an out-of-nowhere 31 back in 2005-6, not coincidentally the one time he's played 82 games. Steven Kampfer hasn't seen much ice time, but he's been excellent with what little he's been given. The only disappointment has been Dennis Seidenberg, the only defenseman with a negative on-ice Corsi to go with his 4 assists in 22 games.
The best news of all is that this excellent play by the Bruins is probably, on the whole, quite sustainable. Kelly should decline, but that loss of production should be made up by Krejci's improvement. Thomas probably won't continue to threaten his all-time save percentage record, but he doesn't need to; the defense is making sure that fewer shots come his way, and Tuukka Rask is playing better than last season. The "hangover" to start the season is a distant memory; forget their status as the 4th place team in the East, Boston's +28 goal differential is the best in the NHL, and indicative of a team that is more than capable of defending the Stanley Cup.