The American League Resumed Interleague Play Dominance in 2021

Okay, so both sides brought representative teams to the AL/NL clash, and the AL won. Does that mean anything?

My first instinct is that it doesn’t. The results of the Tigers-Pirates season series (Pittsburgh won 4-2, for what it’s worth) simply don’t matter if we’re wondering which league is “better.” I also don’t care whether the Rays go 5-1 or 6-0 against the Marlins (they went 5-1). If we want to know who’s better, why not try focusing on teams that might compete for a playoff spot?

Any cutoff is going to be arbitrary, but I decided to look only at teams who won at least 75 games in the 2021 regular season. That excluded 10 teams – six NL squads (Diamondbacks, Pirates, Nationals, Marlins, Cubs, and Rockies) and four in the AL (Orioles, Rangers, Twins, and Royals). Then, I went through the seasonal records with every game involving one of those 10 teams removed.

Nothing changed! The AL went 73-61 in those games, a .545 winning percentage. If “how the teams that are trying do against each other” is a relevant metric, it still looks like the AL is better. Unless you define trying differently, of course – you could cut out teams that didn’t reach 80 wins, or that didn’t make the playoffs, or whatever bright line you prefer, and maybe get a different answer.

Oh yeah, one more thing. The AL edge? It’s actually an AL East edge. In games between the four competitive AL East teams (Boston, New York, Tampa Bay, and Toronto) and the three competitive NL East teams (Atlanta, New York, and Philadelphia), the AL went 35-15. The entirety of the AL’s edge, in other words, came from that absolute dominance.