Wednesday night, the Orioles beat the Angels to vault into a tie for first place in the AL East at 16-8. That tie was short-lived; the Yankees beat the A’s a few hours later to reclaim first for themselves. Meanwhile, the Red Sox beat the Guardians to move to 14-11, the last-place Rays beat the Tigers to get back to .500, and the Blue Jays lost a squeaker to the Royals. It was a good day for the AL East, but what else is new?

Through 93 games of non-divisional play, the AL East teams have accumulated a 57-36 record, a .613 winning percentage. That would be a 99-win pace across a 162-game schedule. They’re tearing the league to shreds. That led me to wonder: Just how good is this start, and what happened to the previous divisions to start this hot?

To solve this problem, I decided to look back through history for inter-divisional records from across the league, because by definition intra-divisional records work out to .500. I started in 1998, the first year with 30 teams, and went from there. But that’s not sufficient, of course. If the East keeps this record up throughout the year, it will end up with the best winning percentage of the 30-team era. But its teams probably won’t keep the pace up. It’s a lot easier to post a .600 winning percentage over 93 games than over the 550 they’ll rack up by season’s end. The best full-season non-divisional winning percentage over that time was .595 by the AL West in 2001, and the Mariners tying the single-season wins record had a lot to do with that.

To account for that, you have to stop your count earlier in the season. Through the same date last year, for example, the AL East had played 81 non-divisional games. Outrageously, its teams had won 57 of those as well, a .704 winning percentage that’s the best, through games of April 24, of any division over this time frame.

Using the exact day isn’t perfect either, though. Through April 24 of 2004, AL East teams had played 18 non-divisional games thanks to a late start to the season. In 1998, they’d already played 95. Still, that provides us an interesting initial benchmark. The .613 clip that the division is currently playing at is a 93rd-percentile outcome, 11th-best over the last 26 years (I’ve excluded 2020 from this analysis for obvious reasons).

As it turns out, we can account for that too. By varying how far into the season we consider each year, we can get a sample of roughly the same size for each season. I say roughly because I didn’t go within a day to cut off each year at exactly 93 non-divisional games. I just looked for the first full day that a division had reached 92 or more games played against non-divisional opponents in each year. And when you look at it that way, the AL East is phenomenally impressive.

The best non-divisional start of this era? That’s still last year’s AL East, with a gaudy .691 winning percentage. But despite that recent outlier, only four divisions have started hotter going back to 1998. There’s also the 2022 NL West (.628), the 2015 AL Central (.614, and wow!), and the 2009 NL Central (.614, likewise). This year’s iteration of the AL East is in a virtual tie for third place, in other words. Here, for your perusal if you’re into excessively large tables, are all the numbers:

How are they doing it? The Orioles and the Yankees are performing most of the heavy lifting, and they’re getting it done in different ways. The Orioles have one of the best offenses in baseball, scoring 5.7 runs per game. The Yankees are allowing 3.5 runs per game, the third-lowest rate leaguewide. Each is roughly average in the other side of the ball, but one average unit and one elite one is enough to build an excellent team. Those two alone have combined to pick up 9.3 expected wins, per our playoff odds model, since the beginning of the year.

The AL East’s dominance is making the rest of the American League look bad. The AL Central has played to a respectable .477 winning percentage so far, but the AL West is at an unfathomable .390, one of the worst starts to a year by a division in the whole data set. There’s a similar effect going on in the NL, too, which brings me to the second half of this article.

The NL East is treading water so far – a .505 winning percentage is respectable but meaningfully worse than both last year’s start and last year’s full season. The NL West has been a tire fire – thanks Rockies! – with a ghastly .417 winning percentage. That leaves the much-derided NL Central, crushing opponents at a .573 clip. In fact, its teams are off to an 89th-percentile start, and that might be more impressive than the AL East being a bit better than advertised.

As it turns out, having a bunch of teams with strong depth and few gaping holes makes for a good division. The preseason favorite Cardinals are the worst team in the division so far, and even they are 11-14. The Cubs and Reds are scoring a ton, 5.4 and 5.3 runs per game, respectively, and coupling that with average pitching staffs. The Brewers have great pitching and great hitting. The Pirates look frisky, and St. Louis isn’t bad for a cellar dweller.

You know how the top two AL East teams have added 9.3 wins to the division’s projected end-of-season total already this year? Overall, the five AL East teams have added 10.2; New York and Baltimore are doing most of the work. The NL Central teams have combined to add 9.9 wins, essentially a dead heat with the AL East, yet every team but the Cardinals has seen its projected total increase by at least 1.5 wins.

As it turns out, your division looks a lot better in inter-divisional play when there are no true cellar dwellers. The White Sox, Astros, Marlins, and Rockies are hurting their respective divisions at the moment. The A’s and Nationals project to do roughly the same going forward. With a team like one of those dragging down a division, it’ll never post a great overall record against non-divisional opponents. The Astros are a shocking 3-15 against everyone outside their division. The Cards and Pirates are off to the worst non-divisional starts among teams in the “good” divisions this year, and they’re both .500.

Is this predictive? I don’t see any reason why it would do better than our playoff odds, so I’ll say no. But it’s certainly informative, and it explains a lot of what the season has felt like so far. The AL East is rolling, the NL Central is hot and full of fun upstarts, and all the other divisions are lagging in their wake, though the AL Central would look pretty good if it weren’t for the White Sox. That’s been my experience watching the games this year, and the win totals bear it out. Let’s check back in a month or so and see if these starts have come close to continuing.

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