For all the talk about conference imbalance in the NBA, basketball isn’t the one professional sport by which one half of the league normally dominates the opposite.1 Since baseball’s Interleague play was introduced in 1997, it has largely served as an excuse for the American League to indicate its superiority: The AL went into the 2018 season having run up a 1,503-1,257 file on the Nationwide League in interleague play over the earlier decade. How good is that? If the common AL staff have been taking part in a 162-game season in opposition to its NL counterpart over that span, it might win 88 video games — roughly adequate to make the playoffs in the NL most seasons.
Why the large disparity? For one factor, the AL has usually had extra star energy: Prior to now decade, eight of the highest 10 gamers in baseball in response to wins above replacement2 (Mike Trout, Adrian Beltre, Zack Greinke, Robinson Cano, Miguel Cabrera, Justin Verlander, Evan Longoria and Dustin Pedroia) hung out within the AL, whereas solely three (Clayton Kershaw, Joey Votto and Greinke) performed within the NL.3 The rule difference that grants AL groups a delegated hitter at house additionally helped them rack up a big home-field advantage through the years.
However up to now in 2018, the AL’s edge has eroded. After a couple of month and a half, NL groups are 32-18 in opposition to their AL foes, outscoring them 242-208. If this holds, it might be the primary time the NL has gained interleague play because the 2003 season.
Clearly, it’s nonetheless early. However even when we restrict ourselves to the primary 50 interleague video games of every season (to make an apples-to-apples comparability with 2018), that is the NL’s finest file in interleague play ever, supplanting its 31-19 begin in 1999. Again then, the NL was aggressive — it ended up successful nearly 54 p.c of its video games in opposition to the AL that 12 months. This season would possibly convey a long-awaited return to its outdated kind.
A number of the causes for the change were emerging final 12 months. The DH just isn’t the advantage it was once; up to now this season, AL designated hitters have an on-base plus slugging (OPS) of solely .725, their worst mark in nearly three decades. Maybe that’s why AL groups are simply 6-19 (a depressing .240 successful share) at house in opposition to the NL this 12 months, a whole reversal of the development that used to fuel American League dominance.
The specter of tanking additionally applies right here. Of the 9 groups monitoring for at the least 88 losses in FiveThirtyEight’s MLB prediction model, six (the White Sox, Royals, Orioles, Tigers, Rangers and Rays) are within the AL. 4 In the meantime, a number of the most improved groups within the majors (such because the Braves, Phillies and Pirates) are within the NL, together with a gaggle of already stable groups who obtained higher over the offseason (the Diamondbacks, Cardinals and Brewers).
Though the AL nonetheless has the benefit in top-line expertise — solely one in all this 12 months’s high 10 in WAR (Nationals ace Max Scherzer) is within the NL — issues seem to have tilted within the NL’s favor general. It’s price noting that the NL has gotten off to a sizzling begin earlier than, solely to crash and burn by 12 months’s finish: In 2016, it gained 30 of the primary 50 interleague video games… then promptly went 105-145 the remainder of the way in which. So we might find yourself wanting again and pondering how cute it was that the NL had such a big early edge on its AL rivals. However at the least there are some causes to suppose this 12 months is completely different, and that the NL’s newfound success is sustainable.