The AL East looks like the best division in baseball again

The past few years, it's been pretty difficult to determine whether the Yankees have gotten "lucky." The team has posted winning records each of the past four seasons despite being on the decline and, in three out of those four seasons, despite being outscored by their opponents. Often, that is a sign of good fortune, though it can also be a sign of timely hitting and excellent bullpen management.

Yet, can a team truly be lucky if it plays one of the toughest schedules in the game? The AL East has long been one of the strongest divisions in baseball. Last year, it was hands-down the best. The Yankees appeared to be a benefactor of Lady Luck when they won 84 games in 2016 despite a negative run differential, but the misfortune of playing in a highly competitive division completely canceled out any sort of Pythagorean luck.

There's a similar dynamic at play here in 2017. The Yankees have surpassed all expectations. They lead the AL East, and they boast the second-best run differential in the AL. Even so, their odds of winning the division and of making the playoffs are far from certain. That's in large part due to the AL East again shaping up to be the best division in the game.

That should seem intuitive just by eye-balling the division. The Orioles over-performing expectations has become almost as inevitable as death and taxes, while the Red Sox are still among the most talented teams in the league even after their middling start. The Rays look average, and while the Blue Jays have struggled, they have a better roster than their record would indicate. That leaves us with a division that has the potential to turn into to a tough three-team dogfight at the top, with a couple of fine fourth and fifth place teams offering little rest for the weary.

Beyond mere intuition, the numbers the division has put up as a whole blow away the rest of the field. Starting with simple run differential, here's how the six divisions stack up:

No other division is particularly close to the AL East, as it is the only division with four teams with positive run differentials, with only the Blue Jays having been outscored. Still, run differential isn't the most nuanced way to describe how good the AL East has been so far. Especially in small samples, run differential can be misleading thanks to the effects of sequencing, and strength of schedule.

So let's turn to Baseball Reference's Simple Rating System (SRS). SRS just takes every team’s run differential and adjusts it for the strength of each team’s slate of opponents. Here's how the divisions look after adjusting for schedule:

After adding another layer of analysis, the AL East has essentially lapped the field, with only the NL Central in the vicinity. This comes as no surprise, as the Al East is the only division in which all five teams sport an SRS that is average or better.

Finally, we can go just a bit deeper, thanks to Baseball Prospectus' adjusted standings. There, BP lists what they call Third Order Winning Percentage. Like SRS, this adjusts for schedule, but instead of using a team's run differential, it uses the run differential a team would be expected to earn based on their underlying batting and pitching lines. Think of it as evaluating teams not based on their runs scored and allowed, but rather, say, their OPS for and OPS against.

Again, the AL East comes out way ahead:

The impact of this is straightforward: even though the Yankees have looked great, the postseason is no sure thing. Their playoff odds sit around 60%, per FanGraphs and BP. Compare that to the Nationals, who have essentially the same record, but boast playoff odds at 95%. Obviously, this comparison isn't entirely fair, as the Nationals' likely have a stronger roster than the Yankees, but much of the certainty of the Nationals’ playoff chances, relative to the Yankees, lies in the pitiful collection of teams the Nats get to feast upon.

If the Yankees were playing this well in another division, the playoffs would look like an excellent bet. Instead, stuck in a loaded division yet again, whether the Yankees make the playoffs as a division winner, a Wild Card, or not at all could come down to the wire. At the very least, they've shown themselves to be up to the task so far.