SEATTLE — Once again, the Seattle Mariners are asking for faith that they haven’t earned.

As they go ever deeper into yet another of their mysterious funks, they want you to believe that it will all turn out well in the end. And it very well might, but right now, they are what their record says they are: A flailing team sitting three games under .500 with an erstwhile ace desperately trying, as yet unsuccessfully, to discover a way of pitching that suits his new reality.

On Tuesday, in a 7-3 loss to Kansas City at Safeco Field, the Mariners continued a troubling line of recent home outings in which they’ve been decisively outplayed, first by the rampaging Astros, then by the pitiful Phillies, and now by the streaking Royals, who are putting together the very midseason surge — 17-6 over their last 23 games — the Mariners have envisioned.

Oh, the Mariners have surged at times this year, tantalizing glimpses of what could be. But lately, during a home stretch in which they’ve averaged just 2.33 runs a game in six straight losses, they’ve looked sluggish, which is a sometimes deceptive byproduct of offensive struggles.

“Guys are putting in the work,” manager Scott Servais, speaking quietly, said after the game. “They certainly care. I know it looks like you don’t care when you’re not hitting. But they do. We’ve got a good club, and we’ll get it going again.”

The Royals of recent vintage are an interesting case study for the Mariners. Now it is Seattle that has a seemingly never-ending playoff drought — 15 years and counting — that tests its fans’ patience and leads to increasing cynicism over each plea that a turnaround is coming. But once it was the Royals who had a far longer postseason drought, a nearly unfathomable 28 years heading into the 2014 season.

That was the year that their rebuilding plan — the latest in a long line of them, but by far the most promising — was going to finally come to fruition. They had a lockdown bullpen, emerging stars, and a veteran rotation anchor in James Shields, a pending free agent who had cost them top prospects, a sign they fully believed that the future was now.

Only the Royals found themselves struggling in the first half, still mired two games under .500 at 48-50 as late as July 21. Some wondered if they’d tear it apart at the trade deadline yet again. Kansas City Star columnist Sam Mellinger lit into them after a particularly dispiriting loss in mid-July: “They are developing quite the reputation for an inability to perform under any modicum of expectation. They are too often at their worst when it matters most.”

But the Royals, too, asked for faith. They held steadfast in the belief that their vision for the season was still sound, and would be ultimately vindicated. And this time, they were right. A stretch of 24 wins in 30 games thrust them into playoff contention, and they held on for a wild-card berth — their first playoff appearance since George Brett’s heyday in 1985.

An improbable 9-8 comeback win over Oakland in the wild card game, followed by sweeps of the Angels and Orioles, put the Royals in the 2014 World Series, and they extended the Giants to seven games before finally falling, with the tying run on third base. The next year, they won it all.

That’s not to say that the Mariners are poised to replicate the Royals’ run to glory. Mariners fans have built up 16 years of reasons as to why that’s a fanciful notion. But what it shows is that for every bereft franchise, there comes a time when you just have to knock down the wall of skepticism. There’s no other way.

I asked Ned Yost, the Royals manager, about all that on Tuesday before the game. I asked him if it was hard, when others were abandoning faith back in 2014, to maintain his.

“No. It wasn’t hard for me,” he replied. “I just know this group and watched it grow, and knew their competitiveness and their desire to win. I just knew that sooner or later they’d get it figured out.

“I also knew that when you bring a group of young guys up together, it takes them about 2 { years before they really start to (jell), and we were at the All-Star break at about that 2 1/2-year point. I figured they were about to take off.

“It happened in Atlanta (where Yost was a coach under Bobby Cox in their breakout years) at the 2 1/2-year mark, and it happened in Milwaukee (where Yost managed from 2003-08). I felt confident it would happen here too.”

These Mariners have a different structure, built around a core of veterans rather than a youthful nucleus all coming of age together (though they have some of that, too).

Servais remains equally bullish, but the time of reckoning is coming for the 2017 Mariners.

They have the benefit of a tightly bunched wild card race that allows a team to remain one hot streak away from realizing its dreams, even in the midst of struggles. Right now, they are pressing, Servais said, every player trying to be the one to come up with the big hit that propels them out of their funk. They need Felix Hernandez, battered for six runs in six innings on Tuesday, to settle into a game plan befitting a pitcher who no longer can overpower opponents.

“We need to get some momentum going,” Servais said.

There’s still time. There is still opportunity. And, I’m convinced, there’s still enough talent on this team to mount a strong playoff run.

But by now, at this stage of their evolution, 15 years in, the Mariners aren’t going to get much help in the faith department. They’ve got to earn that. They’ve got to knock that wall down.