Despite their recent winning streak, the Seattle Mariners are unlikely to make the postseason. Our Elo simulations project Seattle to finish with a respectable 87 wins, but the team still has a comparatively slim 34 percent chance of making it to a wild-card game. So unless their hot streak persists for a few more weeks, the Mariners will probably extend their MLB-record playoff drought to 15 seasons. This set of circumstances — Seattle winning a good amount of games but failing to make the playoffs — is nothing new: Although the Mariners have hardly been uniformly great during their drought, no franchise has had more bad luck keeping it out of the playoffs over the past couple decades, given its yearly records.

Since they tied the all-time MLB record for wins in a season with 116 in 2001, the Mariners have assembled a handful of competitive teams, winning between 85 and 93 games in a season five times since. (This doesn’t include 2016, when they’re likely to do it again.) None of those seasons are good enough to guarantee a playoff spot, but each should have given the team a reasonable chance to back into a wild card or steal a weak division. And yet, Seattle has nothing to show for those seasons. To determine just how unlucky the Mariners have been in this regard, I looked at how many wins are typically associated with making the playoffs using data since 1998, the last time MLB expanded.

The interesting part of the playoff probability curve typically ranges from around 81 wins (where a team would have practically no shot at the postseason) to 96 wins (where a team is practically guaranteed at least a wild-card slot). A team’s chances of making the playoffs at each win increment between those extremes depends largely on the luck of the draw — specifically, how many games were won by the other teams in the division and the league.

The the introduction of a second wild card has made the biggest difference for good teams on the edge of the playoff bubble. (Think teams sitting in that 86-to-91-win zone.) Under a single-wild-card system, a hypothetical team in this group should only make the playoffs about 38 percent of the time. With two wild cards, that probability jumps up to 62 percent.

But back to the Mariners. For each franchise, going back to 1998, I used the above formula to calculate the yearly probability that it would make the playoffs based on how many games it won. Then I summed up the probabilities to measure how many playoff appearances a given team should have collected over that span, compared to how many appearances it actually made.

TEAM PREDICTED PLAYOFF APPEARANCES ACTUAL DIFFERENCE 1 Seattle Mariners 4.20 2 -2.20 2 San Francisco Giants 7.60 6 -1.60 3 Boston Red Sox 10.60 9 -1.60 4 Los Angeles Angels of Anaheim 8.20 7 -1.20 5 Toronto Blue Jays 2.00 1 -1.00 6 New York Mets 4.80 4 -0.80 7 Cleveland Indians 5.70 5 -0.70 8 Chicago White Sox 3.60 3 -0.60 9 Cincinnati Reds 3.50 3 -0.50 10 Tampa Bay Rays 4.40 4 -0.40 11 Washington Nationals 2.40 2 -0.40 12 Oakland Athletics 8.30 8 -0.30 13 Baltimore Orioles 2.20 2 -0.20 14 Kansas City Royals 2.00 2 +0.00 15 Miami Marlins 1.00 1 +0.00 16 Philadelphia Phillies 4.80 5 +0.20 17 Texas Rangers 5.80 6 +0.20 18 Milwaukee Brewers 1.70 2 +0.30 19 Detroit Tigers 4.70 5 +0.30 20 Pittsburgh Pirates 2.60 3 +0.40 21 San Diego Padres 2.50 3 +0.50 22 Los Angeles Dodgers 6.50 7 +0.50 23 Arizona Diamondbacks 4.50 5 +0.50 24 Colorado Rockies 1.40 2 +0.60 25 New York Yankees 14.10 15 +0.90 26 Atlanta Braves 10.00 11 +1.00 27 Minnesota Twins 4.80 6 +1.20 28 Houston Astros 4.70 6 +1.30 29 Chicago Cubs 3.70 5 +1.30 30 St. Louis Cardinals 9.80 12 +2.20 Unluckiest MLB franchises since 1998 Source: Lahman Database

Most teams are within a playoff appearance or so of their actual numbers, but the outliers on either end are striking. The most unlucky franchise in baseball is the Mariners, who should have earned 4.2 playoff appearances since 1998 but instead have managed only two (and none since 2001). None of the reasonably strong Seattle teams scattered over the past 15 years have yielded a postseason appearance, with the two 93-win squads (in 2002 and 2003) standing out as the largest outliers — both should have been good enough to make the playoffs about 87 percent of the time under normal circumstances. Although Seattle’s home division, the American League West, has also averaged the most wins per team-season of any division since 1998, the West’s winners haven’t been especially strong (they’ve averaged only the third most wins of any division’s winners), which suggests the Mariners can blame only part of their misfortune on their closest competition. Likewise, my model didn’t find the yearly strength of the American League as a whole to be a significant factor in depressing Seattle’s playoff probability either.

Meanwhile, at the opposite end of the spectrum, the St. Louis Cardinals have been baseball’s luckiest team in terms of gaining extra postseason berths. And no season better exemplifies this than 2006, which saw the Cards win the World Series despite posting a mere 83 wins and +19 run differential. Given that resume, they would have been predicted to have only a 1-in-40 chance of making the playoffs. But even disregarding that 2006 team, every single one of the 11 St. Louis squads with more than a 50 percent postseason probability in my model went on to make the playoffs, including five times when the Cardinals’ chances were under 90 percent. And that’s on top of repeatedly harnessing improbable streaks of luck to achieve those records in the first place.

Maybe the Cardinals have found another way to harness their devil magic. But the Mariners’ bad fortune is probably mostly random. With the margins for making a playoff spot as thin as a few games, an ill-timed loss here or there can be enough to turn a promising season into October misery. Although Seattle’s luck will turn around eventually, you’ll have to forgive the team’s fan base if they’re skeptical after years of heartbreak.