Bottom line: The Tigers finished 12.6 wins below their expected record, the largest gap in baseball, and the Rays rode a Luck Index of 86 to a postseason spot.
Through October 18, 2026, the final regular-season numbers are locked in, and the divergence between what happened and what should have happened is striking. Per Baseball Savant's Statcast data and expected-record models, six teams stood out as the most extreme cases on the MLB luck rankings this season. Three of them were punished by variance. Three were rewarded by it. The playoffs are now underway, and these gaps offer a useful lens for anyone watching the lines shift.
The luck score methodology here is straightforward: compare a team's actual win-loss record against the record implied by its run-scoring environment, then layer in sequencing, bullpen leverage, and one-run game outcomes. A negative number means the baseball gods took something away. A positive number means they were generous.
Due a Correction
The Detroit Tigers posted the most severe negative luck score in baseball at -57, finishing a staggering 12.6 wins below their expected record. That is not a rounding error. Detroit's run differential pointed to a team that should have been in the wild-card conversation, not watching October from home. Their Statcast batted-ball metrics, particularly barrel rate and expected slugging, told the story of a lineup that hit the ball hard and got nothing for it. Sequencing was brutal.
The San Francisco Giants came in at -55, with an xPoints gap of -6.6. Six and a half wins vanished into the ether, largely through a one-run record that defied their pitching staff's actual quality. Their bullpen ERA sat a full run above its expected ERA, suggesting the kind of small-sample cluster luck that rarely persists across a full calendar year, except when it does.
The New York Mets rounded out the unluckiest trio with a luck score of -50 and an expected-win gap of -3.7. A smaller deficit than Detroit's, but notable for a team that spent most of the summer on the fringe of contention. Variance of this size over 162 games tends to cluster in high-leverage situations, and the Mets' record in games decided by two runs or fewer bears that out.
Living on Borrowed Luck
| Team | Luck Index | xWin Gap |
|---|---|---|
| Rays | +86 | +7.8 |
| D-backs | +49 | +4.1 |
| Reds | +42 | +9.8 |
The Tampa Bay Rays earned the highest positive luck score in baseball at 86, outperforming their expected record by nearly eight wins. Their one-run game record was, predictably, absurd. The Rays have long been an organization that manufactures edges in close games through bullpen management, but even by their standards this season's margins were narrow enough to suggest fortune played a leading role.
The Arizona Diamondbacks at +49 were a quieter case, four wins above expectation, but their underlying pitching metrics suggest a staff that was saved repeatedly by sequencing. Hard contact allowed did not match runs allowed.
The Cincinnati Reds may be the most fascinating outlier. A luck score of +42 paired with the largest raw xWin gap on the overperforming side at 9.8. Nearly ten wins above where the run environment said they should be. That is a number that, historically, corrects violently.
Ten wins is a lot of borrowed luck.
The Regression Window
In baseball, season-long luck gaps of this magnitude have historically corrected within the first 40 to 60 games of the following season. For the teams still playing in October, the correction window is even smaller. A five- or seven-game playoff series is a notoriously small sample, which means variance can persist, or it can snap back in a single afternoon. Bookmakers tend to price playoff lines off recent performance rather than full-season expected metrics, which means the market is often slow to account for these gaps. That inefficiency is visible in the numbers. What anyone does with that visibility is, of course, entirely their business.