MLB's Postseason Is A Tale Of Two Leagues
WALLY SKALIJ / LOS ANGELES TIMES VIA GETTY IMAGES
Remember all those big favorites going into the MLB postseason? The record-tying four 100-plus win teams from the regular season? The 20-win gaps between best and worst seeds in each league? The theoretical advantage of a first-round bye for top teams under MLB’s new playoff system?
Turns out only one league got the memo about the big disparity between baseball’s haves and have-nots this season.
Over in the National League, chaos has reigned supreme. After the lower seeds won both wild card matchups, the San Diego Padres and Philadelphia Phillies kept that energy going in the divisional round as well, knocking off the heavily favored Los Angeles Dodgers and Atlanta Braves, respectively. Whether you look at the magnitude of those upsets through the lens of regular season win-loss records — both series’ losers had outplayed their opponents by more than 85 points of winning percentage — or our pre-series Elo ratings, the Padres and Phillies pulled off two of the biggest division-series shockers since the round began in 1995:
Two ways of measuring the divisional round’s biggest upsets
Largest gaps in regular-season winning percentage and pre-series Elo rating between an underdog and favorite in MLB division series upsets, 1995-2022
| Year | Winner | Loser | Gap | Year | Winner | Loser | Gap | |
|---|---|---|---|---|---|---|---|---|
| 2022 | SDP | LAD | -.136 | 2022 | SDP | LAD | -82.1 | |
| 2020 | HOU | OAK | -.117 | 2001 | NYY | OAK | -77.6 | |
| 2022 | PHI | ATL | -.086 | 2002 | MIN | OAK | -67.8 | |
| 2008 | LAD | CHC | -.084 | 2003 | CHC | ATL | -54.3 | |
| 2003 | CHC | ATL | -.080 | 1998 | SDP | HOU | -52.6 | |
| 2019 | WSN | LAD | -.080 | 2021 | BOS | TBR | -51.8 | |
| 2011 | STL | PHI | -.074 | 1996 | BAL | CLE | -48.9 | |
| 1996 | BAL | CLE | -.072 | 2022 | PHI | ATL | -48.7 | |
| 2017 | NYY | CLE | -.068 | 1997 | CLE | NYY | -43.5 | |
| 2012 | STL | WSN | -.062 | 2017 | NYY | CLE | -40.3 |
Meanwhile, over in the American League, a measure of sanity was restored with division series victories by the top-seeded Houston Astros and New York Yankees. It wasn’t exactly easy in either case — the Astros required a pair of one-run victories (the latter of which tied a playoff record at 18 innings) to finish off the Seattle Mariners, while the Yankees had to overcome a 2-1 series deficit against the Cleveland Guardians to advance — but the best teams in the league all season will be playing for the AL pennant.
This sets up an odd juxtaposition between the two championship series. Both are very nearly coin flips in our model — the Astros have a slim edge over the Yankees (54 percent to 46) and the Padres are even slimmer 52-48 favorites over the Phillies — but the combined quality of the two teams in each league could scarcely be more different. The gap between the average Elo rating for the championship contenders in the AL (1578.7) and the NL (1539.9) is 38.8 points. Going back to 1995 again, that’s the biggest differential in the combined quality of LCS teams in one league versus the other in any postseason:
The biggest disparities in LCS quality of the wild card era
Biggest gaps in average Elo rating between MLB teams in one league’s championship series and the other’s, 1995-2022
| Year | Lg | Teams | Avg. Elo | Lg | Teams | Avg. Elo | Gap |
|---|---|---|---|---|---|---|---|
| 2022 | AL | HOU, NYY | 1578.7 | NL | SDP, PHI | 1539.9 | +38.8 |
| 2021 | NL | ATL, LAD | 1587.1 | AL | HOU, BOS | 1549.5 | 37.6 |
| 2007 | AL | BOS, CLE | 1569.3 | NL | ARI, COL | 1537.3 | 32.0 |
| 2019 | AL | HOU, NYY | 1589.0 | NL | STL, WSN | 1559.5 | 29.4 |
| 2008 | AL | TBR, BOS | 1566.5 | NL | PHI, LAD | 1537.3 | 29.2 |
| 2009 | AL | NYY, ANA | 1575.7 | NL | LAD, PHI | 1547.5 | 28.2 |
| 2018 | AL | BOS, HOU | 1599.3 | NL | MIL, LAD | 1571.6 | 27.7 |
| 2014 | AL | BAL, KCR | 1554.6 | NL | STL, SFG | 1530.0 | 24.7 |
| 2003 | AL | NYY, BOS | 1560.6 | NL | CHC, FLA | 1536.2 | 24.3 |
| 2011 | AL | TEX, DET | 1558.6 | NL | MIL, STL | 1534.5 | 24.1 |
(Interestingly, it just edges out last year, which featured elite Braves and Dodgers teams in the NL but a less-heralded run by the Boston Red Sox to drag down the AL’s average.)
As a consequence, the ALCS winner should be heavily favored in the Fall Classic, as our model says there’s a 65 percent chance the World Series winner will come out of the AL. But that all depends on which league’s postseason narrative — chaos in the NL, or order in the AL — holds the upper hand by postseason’s end.
Check out our latest MLB predictions.