A couple of months back, I’d written about how the NL Central was playing the best baseball of any of the game’s divisions. As we come to the merciful end of interleague play this weekend, the NL Central has collectively slipped under .500, while the cream of the game has risen to the top. Rapidly. Here are the divisions’ interdivisional records through Thursday:

            W    L    Win%
AL East    134  108  .554
NL West    103   95  .520
AL West    102   96  .515
NL Central 111  113  .496
AL Central 108  123  .468
NL East     96  119  .447

It looks more and more like the superiority of the AL, which we’ve come to take as a given, is actually a superiority of the AL East. Remember, the two leagues aren’t distinct entities any longer, but conferences within one league. They operate under the same rules, they acquire talent in the same draft and have the same setups in the minor leagues. There’s no structural reason why one league should be better. For a generation after World War II, the National League ran out ahead of the American League because it integrated more quickly, tapping into the reserves of African-American talent made available in the wake of Jackie Robinson‘s debut. There’s been no change like that in MLB; I might argue that the AL has had more success in bringing over Japanese players-other than Hideo Nomo, the top NPB successes over here have played for AL squads-but that’s nothing like the NL’s better integration practices in the 1950s.

However, the competitive pressures of the divisions, and in particular the competitive pressures of two highly-successful, high-revenue, high-payroll monsters, sets a bar in the AL East that has to be met. That’s why the Rays, who might have wandered into contention in the early 2000s in a different locale, had to be sold and implement an entirely new and different-thinking management team to be successful. It’s why the Orioles, with no hope of contending through marginal improvements, brought in Andy MacPhail and gave him both the authority and the resources to change a decade of failed policies. The Blue Jays have put together so much pitching depth that they’ve been able to survive the complete loss of a rotation. That is a credit to a GM, J.P. Ricciardi, who I’ve frequently criticized. The Jays may, over a three-year period, be one of the top five teams in baseball, and nevertheless end up with absolutely nothing to show for it.

The AL is once again slamming the NL in interleague play, with a 113-96 mark (.541) with 43 games left to play. Barring at least a 29-13 weekend by the NL (there’s a dangling Cubs/White Sox game to be played), the AL is going to win interleague play for the sixth straight season, and there’s a good chance that for the fifth in a row, it won’t be close. In this case, each division is carrying its own weight: every AL group is above .500 in interleague play, as are nine of the 14 teams in total. Over in the NL, the West is .500, the other two divisions below. Just five teams are above .500 against the AL.

The Adjusted Standings, which take into account not just wins and losses, but the underlying quality of play and the overall strength of schedule, are perhaps the best indicator of the quality gap. By third-order record, four of the top seven teams in baseball are AL East teams, with the Rays-fourth in their own division-arguably the best team in baseball, same as a year ago. Bullpen problems and some bad luck have done a good job of hiding how well they’re building on last year’s foundation. The Toronto Blue Jays are the seventh-best team in baseball. The bottom five teams in the National League, the Giants, Reds, Nationals, Astros and Padres, are all worse than the A’s, bringing up the rear in the AL. It actually could have been worse for the NL; the Dodgers are clearly their best team, and had they not signed Manny Ramirez and Orlando Hudson as winter turned to spring-had, say, the Angels picked up one or both players, or the Angels Ramirez while the Twins ink Hudson-the AL could conceivably have the four best teams and maybe seven of the top eight.

Fundamentally, the AL is a .520 league, the NL a .480 league. The AL is six games better over a full season (84-78 vs. 78-84). However, that difference is entirely about the AL East. The average American League East team is a 91-71 team. No other MLB division is even at .500, although the AL Central pretty much rounds to 81-81:

AL East    .564
AL Central .498
AL West    .494
NL East    .488
NL West    .485
NL Central .474

That’s complete and utter dominance of the sport, akin to what a great college basketball or football conference might be in any given year. Or perhaps to what the best division in the NBA’s Western Conference might have done at that group’s peak. It’s an imbalance the likes of which we’ve rarely seen, and which we’re certainly not accounting for in evaluating both the AL East teams and the teams around the league. The four best teams in the AL are all in the East, and two will have to stay home so that two of the Tigers, Twins, Rangers, and Angels can populate October. I wouldn’t necessarily call that unfair, which is a loaded word, but I do think it’s a shame that we’ve gotten to a point where the best teams in baseball are so unevenly distributed as to leave so many good ones home. Some fundamentally 90-win team like the Jays is going to miss the playoffs so that we can watch at least one, maybe more, fundamentally .500 teams play on. The Orioles, no one’s idea of a contender, would be in the mix for the National League Wild Card.

So watch the Yankees and Mets this weekend, and the Jays and Phillies, and the Rays and Marlins, and think less about the gap between their actual records and more about the gap between what they really are. The AL East is simply playing a different game than everyone else is.