Final Day of MLB Regular Season Holds Drama, But History Made

When Major League Baseball altered its schedule to have all 15 games commence within moments of one another on the final day of the regular season, Sunday was, well, the day they had in mind. Mostly, anyway.

Most postseason positions were nearly set in the days leading up to this final day, yet two notable races were still running hot. In the American League West, the Houston Astros and Texas Rangers were locked in a tie with records of 81-81, which was quite astonishing. Meanwhile, in the National League, the race for the third wild card spot was between the Philadelphia Phillies and Arizona Diamondbacks.

The Phillies, who just a week prior had a staggering 99.1% chance of making the postseason according to FanGraphs, managed to avoid a historic collapse. They secured their wild card series appearance with a 7-3 victory over the Tampa Bay Rays.

A Historic Low for the Astros

But it was the Astros who, despite their win, found themselves making a somewhat embarrassing piece of history. They officially became the worst division-winning team in baseball history. The previous record was held by the 2005 San Diego Padres, who won the NL West with an 82-80 mark. Even with a 9-0 victory against the already eliminated Athletics, the Astros’ 81-81 record set a new low for winning percentage by a division champion in a full season.

Interestingly, the Astros were almost fortunate to finish the season with a .500 record.

Wins and losses shape standings, but run differential is often a better indicator of future performance. Statistically, outscoring opponents typically forecasts more victories. One-run games can’t be relied on long-term, but blowout wins give insight into a team’s true ability.

Run differentials can also be used to estimate “expected” records. For instance, the Miami Marlins had just a three-run advantage over their opponents, leading to an expected record of 81-81. It’s logical, right? They performed evenly against other teams; thus, they ended up even.

Conversely, the Milwaukee Brewers led the league with a +214 run differential, translating to an expected record of 103-59, which they actually achieved.

However, it’s common to see teams either overperform or underperform relative to their expected records due to various factors. An ineffective bullpen could help a team in lopsided wins while causing losses in closely contested games. Then there are injuries, defensive troubles, inconsistent hitting in crucial moments—the unpredictable nature of baseball plays a significant role. Not to mention, having a reliable closer helps seal close games.

This year’s Astros, with their 81-81 record, finished the season having actually been outscored by 32 runs, which predicted an expected win-loss record of merely 78-84. The Rangers, who ended up missing the postseason, had an even worse -46 run differential and a 76-86 expected record.

In short, these teams are not performing at a high level.

So, one might assume that Houston will likely bow out of the playoffs quickly, right?

Well, not quite. The Astros are set to face the Chicago White Sox in a best-of-three wild card series, which they will host due to their division title. Although Chicago is the stronger team, the random nature of playoff series adds an element of uncertainty. In fact, FanGraphs gives Houston a 55% chance of advancing to the ALDS.

If the Astros pull off that victory, they would then face the Cleveland Guardians, who, despite finishing with a mediocre +11 run differential and a record of 85-77, are perhaps slight favorites at 57-43. It’s not an impossible road for an 81-81 team to think they could reach the ALCS.

The league had always aimed for dramatic moments on the last day of the regular season by scheduling all the games simultaneously. And they certainly got that.

Yet, they also witnessed the weakest division-winning team in history, a consequence of financial incentives and the league’s playoff structure that encourages owners to do as little as possible—spending minimally to scrape by with just enough wins. In Houston’s case, that meant winning 81 games, while fans watched their team “battle” through a notably unexciting AL West.