It wasn’t supposed to be this way. The rotation was thin. The stars were old. The bullpen was untested. The bench was short. The Mariners were built to hang out, not to thrive, like a gangly youth in a Sum 41 graphic t-shirt that was either serious or ironic depending on which crowd they ran with. Yet 72 games into the season the Mariners are 46-26, within a hair’s breadth of the AL West division lead and league-wide desolation, creating a five and a half cart race for a playoff spot. There’s a long way to go yet, but if Seattle finds themselves playing into October it will be thanks to a more nontraditional kind of depth.

In years past the Mariners have pushed to the brink of playoff berths with teams hitched to starry stallions. In 2014, Kyle Seager, Robinson Canó, Félix Hernández, and Hisashi Iwakuma dragged a listless offense to 88 wins and a Game 162 that mattered. 2016 saw Canó and Seager joined by Nelson Cruz as the beasts of burden dragging the Mariners’ cart to a heartbreaking Game 161.

This year, Seager is 9th on the team in wRC+ among full-time players. Robi is out until mid-August, and ineligible for the postseason, which is not the scoff-worthy footnote it would be previously. Félix has vacillated between competency and catastrophe. Nellie is, well, still amazing, but has been limited by multiple lower body injuries. Kuma is 38 and has yet to throw in a game since sitting in the low-80s at the outset of 2017, and subsequent shoulder surgery this offseason.

Yet the playoff drought has never looked more quenchable. Much of that has to do with Seattle’s offense, which currently ranks 9th in MLB in non-pitcher wRC+ at 108, and boasts a healthy .260/.322/.424 line. The teams the Mariners faced this week - the Angels and the Red Sox - have extremely similar cumulative stats, ranking 10th (107 wRC+) and 4th (109 wrC+) respectively, but the pathways to the achievements have been drastically different.

The Angels famously are built on Mike Trout and the Minnows, but it’s unfair to say he’s been alone in excellence. Andrelton Simmons, Justin Upton, and Shohei Ohtani all join him above 120 wRC+ and OPSs from .798 to 1.147 (three guesses on who that is). The trouble is Anaheim’s next-best hitter has a 91 wRC+ and is their full-time 1B/DH, with an OPS of exactly .700. Boston is better distributed and fares more favorably by OPS, thanks to the little old Mookie who lived in the shoe-sized stadiums of the AL East, but the offensive production is similarly feast or famine. Boston’s lineup can boast five or six above-average hitters, but also routinely runs out three or four eggs.

That’s not an indictment. Boston is an incredible team, but it helps frame why the Mariners have succeeded differently than this week’s opponents. I pulled the numbers from each hitter with at least 100 plate appearances so far this year and matched them up. The Mariners lack the star power of the AL’s other giants, but they have competency at every point in their starting lineup, which has its own rewards.

Clearly the Mariners don’t have anyone who can swing it like Trout or Mookie. It takes a while before the M’s set themselves apart in any of the groupings, but as the Angels begin to flag behind their big four, the Mariners continue to perform well. Seattle’s worst hitter is Dee Gordon, whose 85 wRC+ doesn’t track his elite baserunning. They boast seven above-average (aka >100 wRC+) hitters, six of whom are active and playoff-eligible, and, just as importantly, no black KColes holes dragging down the lineup. The top-to-bottom decency of the lineup may even have a role in Seattle’s late-game heroics, as the 7-8-9 of the Mariners’ order ranks 3rd in MLB in wRC+ (105) from the 7th inning on.

Seattle’s balance from 1-through-9 in the order is not depth in the sense that they have elite reinforcements available in the minor leagues; they most certainly do not. The depth they’ve been able to lean on is all in the starting lineup. This isn’t a “better” approach than the way Boston is constructed, it’s a different way. This winter, John LaRue studied styles of team construction in the past 30-40 years for The Hardball Times and attempted to categorize what was most successful. Stars and Scrubs? Depth? Unsurprisingly, the answer was Stars and Depth, but given a decidedly Stars and Scrubs roster after 2015, the 2018 Mariners are continuing a trend away from relying on Canó, Seager, and Félix.

Last September I wrote about how the Mariners’ stars had let them down, but that the blame for 2017’s disappointment was far more to blame on the rest of their roster. Last year the bottom of the barrel was rotten, but an update to the chart from that piece shows Seattle has their depth to thank for their success thus far.

Seattle’s “stars” have been brilliant, as Mitch Haniger, Jean Segura, James Paxton, Edwin Díaz, and Marco Gonzales have stabilized the Mariners, but the rest of the roster has picked up the slack, particularly within the starting lineup. The M’s have suffered numerous injuries and been forced to fill in replacement-level (or worse) players, highlighting their lack of depth in the dugout and Tacoma, but because Seattle has relative competency at every spot in their healthy lineup, they’ve managed to deaden the blows.

Seattle’s priority should still be upgrading their bench, and the lack of impact on the horizon in the minors remains dangerous. In 2018, however, the depth of their lineup is keeping the Mariners in games and pushing them ever closer to the playoffs. Maybe Mike Zunino was right.