Of all the storylines to watch as Major League Baseball begins the second half of the 2018 season, the most interesting might be whether the Seattle Mariners can hold on to their current position in the standings — and, in the process, end the longest active postseason drought in major professional sports. (The Mariners earned this dubious honor when the Buffalo Bills grabbed an AFC wild card last season.)

It’s been a magical start to the summer so far in Seattle. Picked preseason to finish around .500, the Mariners instead sit nearly 20 games over that benchmark. Surprisingly, they spent much of the first half challenging the defending champion Houston Astros for the top spot in the American League West; they’ve also built for themselves a three-game cushion over the division-rival Oakland A’s in the race for the AL’s second wild card. (And they’ve done it even after losing star second baseman Robinson Cano, who was putting up great numbers before getting busted for steroids in mid-May.) If the regular season ended today, the M’s would finally be back in the playoffs.

That would be a major accomplishment for a Seattle club that hasn’t tasted postseason baseball since its disappointing five-game exit from the American League Championship Series 17 years ago. When my former colleague Rob Arthur wrote about the Mariners’ streak a few seasons back, he found that no team in baseball had made the playoffs fewer times relative to expectation (based on their regular-season records) since 1998 than Seattle. It’s undeniable that, with just a little better luck, the Mariners would have sneaked into the playoffs at least a few times over the span of their drought. In that regard, they are long overdue to catch a break.

In 2018, however, Seattle might be collecting all of the extra good fortune it’s owed at once. According to The Baseball Gauge, no first-half team exceeded its expected record more through luck in close games or favorable “sequencing” than the Mariners. For instance, if you simply looked at Seattle’s runs scored (412) and allowed (414), you’d think it was precisely the .500-ish team that the preseason projections had called for. Instead, the Mariners have gone 26-12 in one-run games, which — while not exactly in 2016 Texas Rangers territory — suggests they could be due for a serious second-half downturn.

In fact, Seattle’s combination of win-loss record and negative run differential is so unusual that it’s tough to find similar historical teams. Since 1950, the Mariners are the only team to be 19 games over .500 through a similar stage of the season while also having a run differential below zero. But if we just limit ourselves to the 13 teams that were at least 10 wins above .500 and had outscored opponents by 10 runs or fewer through 97 games, those clubs won only 51 percent of their games over the rest of the season (an 83-win pace per 162). So the Mariners probably shouldn’t expect to keep cruising along at a clip remotely close to their current .598 winning percentage.

Indeed, if the wheels do fall off for Seattle, naysayers may point to the team’s poor play just before the All-Star break — eight losses in its last 11 games — as a sign of when things started to go wrong. But ace pitcher James Paxton will be back from the disabled list soon, and Cano is eligible to return Aug. 14. Meanwhile, the time off should benefit the slumping quintet of Kyle Seager, Jean Segura, Dee Gordon, Ryon Healy and Nelson Cruz, each of whom seemed to be running out of gas heading into the break.

In the bigger picture, there’s also something to be said for the team’s overall balance as an antidote to the notion of an impending collapse. The Mariners are one of only six teams in baseball to rank among the top 10 in wins above replacement from both its pure hitting and its pitching, joining the Astros, Red Sox, Yankees, Indians and Dodgers — pretty good company! Of course, that brushes aside Mariner weaknesses such as baserunning (they rank 24th) and fielding (20th), but it also underscores that despite Seattle’s uninspiring run differential, the fundamentals of the team aren’t necessarily unsound.

In order to stay on course for the playoffs, Seattle will need to keep getting unexpected performances like the ones they’ve enjoyed from first-time All-Star Mitch Haniger and journeyman-turned-10-game winner Marco Gonzales. Closer Edwin Diaz (who leads baseball with 36 saves) will have to keep slamming the door shut in the ninth inning, and the lineup will need to continue hitting well in big moments. None of that will be easy, especially not with Oakland zooming up in the rearview mirror. But after nearly two decades of the pieces never falling into place for a postseason push, it’s high time the Mariners had the breaks go their way.

Check out our latest MLB predictions.