With Toronto off to a 6-1 start despite once again being consistently outshot in games, it looks the Maple Leafs are going to draw an lot of the focus from both the hockey stats crowd and the more traditional hockey watching communities alike this season.
The Leafs have been winning games despite usually trailing in terms of possession, making up for it through their percentages. A big factor in that is the sky-high 13.1% team shooting percentage, which may or may not be somewhat accounted for by talent and/or style of play, but here I'm going to focus more on the defensive/goaltending side of the equation.
The narrative from fans and talking heads is that the Leafs are willing to trade quantity for quality on the defensive side of the puck, keeping shots to the outside while taking away the dangerous areas of the ice. I think that the overall numbers still suggest that shot quality effects in today's league are fairly minimal, but we're dealing with a single team here and it's at least possible they could be an outlier. Yet an even bigger problem with the conventional wisdom is that it is completely contradicted by the situational goaltending stats. Toronto goalies aren't putting up great numbers because their teammates are taking away the key areas of the ice at 5 on 5. Their outstanding save percentages are on the penalty kill, a game situation where every team around the league tries to take away the key areas of the ice because that's basically the only strategic option a shorthanded unit has at its disposal.
Breaking down Toronto goaltending over the last two seasons by game situation, we get:
Even strength: 1383/1497, .924
Penalty kill: 222/244, .910
Power play: 42/44, .955
League averages from 2012-13 were .920, .865 and .918 respectively. That means the Leafs were 5.1 goals above average at even strength and 12.5 goals above average on special teams. There were an additional 1.6 goals saved because the team faced fewer than average shots against while shorthanded, which means that adding it all together, special teams accounted for just 16% of shots against but 73% of the team's goals saved above league average.
The penalty kill numbers from 2012-13 also buck the narrative that high save percentages were related to a team strategy of letting opponents fire away at will from the harmless areas of the defensive zone. The Leafs were an elite PK unit in terms of shot prevention, allowing just 41.8 SA/60, good enough for 5th best in the league. Compare that to even strength where nobody allowed more shots against per minute than Toronto's 33.7.
So far the 2013-14 numbers are pretty consistent at evens (33.4, 7th worst), but the PK is also getting lit up on the shot clock with 63.6 SA/60, the 6th most league-wide. I'd expect that number to drop as the season wears on, but if it continues to remain high then any save percentage regression is going to hit Leaf special teams awfully hard.
It could be argued that Toronto's shorthanded unit is so good that it reduces shot quality against, but there's no way it could account for the entire effect: Any given power play shot has been 49% more likely to go in against a league average goalie than against a Toronto netminder since the start of last season. It should also be noted that Randy Carlyle does not have a history of seeing his teams record amazing save percentages on special teams, despite some pretty good goaltending overall. The highest number any of his Anaheim teams recorded on the PK was .889, and from 2005-06 to 2010-11 Duck goalies had a very ordinary special teams split (.926 at even strength compared to .877 on the PK, along with .910 on the power play).
I think Jonathan Bernier and James Reimer are a solid duo and have the talent to make an above-average tandem, but I don't think that Toronto's shorthanded save percentage is in any way sustainable. The jury may still be out on how much Toronto's scoring performance is based on shooting talent and/or counterattacking skill, but the defensive shot quality arguments look pretty weak to me. Evidence suggests that the Maple Leafs are being carried by some good goalies running unusually hot on special teams, and if that's true then the smart bet is that their save percentage numbers are going to regress pretty strongly over the rest of the season.