SEATTLE -- The Rays’ postseason aspirations will hinge heavily on how their fill-in starters carry the load of their All-Star caliber cast currently on the shelf. They need length and quality, which is why the club is deploying starters conventionally for their three-game series in Seattle, and potentially beyond.

First up was left-hander Jalen Beeks, who instead treaded water in ways that continue to sink him early in outings. Tampa Bay meandered its way to a 5-3 win after breaking a 2-2 tie in the ninth on three walks, an error and a fielder’s choice. Most chiefly, the Rays held onto the second American League Wild Card spot by a half-game over the A’s. But the lack of length from Beeks could be a concern.

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With Blake Snell, Tyler Glasnow and Yonny Chirinos each out until September, and with the Rays teetering on postseason contention despite holding a playoff spot in 121 of 135 days, their August stretch is perhaps even more vital to their fate.

It’s no longer conducive for the Rays to deploy an opener three times per week, at least not with the rotation currently depleted, which leaves much-needed innings to Beeks, who began the season in a setup role, and Ryan Yarbrough, who had largely been a middle-innings reliever before the Rays’ attrition.

“I didn't do a very good job of getting ahead of guys, in general,” Beeks said. “I can hang my hat that I battled, but just going forward, I've just got to get ahead of guys with all three pitches a little better and get in a little better rhythm. ... I've just got to do a better job of being more aggressive and getting in the zone. I mean, that's the goal from here on out.”

Against a Mariners lineup that’s been no-hit twice this season, Beeks got behind often, worked his way into five three-ball counts and exited after 85 pitches over just 3 2/3 innings -- all after Rays manager Kevin Cash preached the urgency of Beeks going at least five frames, and hopefully more.

Beeks’ continued struggles to find a rhythm with the refined delivery he installed this season are having reverberating effects on how Cash deploys the rest of his pitching staff. For example, he had to turn to Colin Poche, his lone lefty, to get out of Beeks’ jam in the fourth.

“That's not ideal. We've got to be better than that,” Cash said. “You've got to be more efficient than that. He recognizes that. Seattle saw a lot of pitches, laid off, didn't expand off of them very much. They found some holes. Didn't necessarily square everything up. But at the end of the day, any starter would tell you that 85 pitches just doesn't work.”

To be sure, the Rays still found a way to win on a night where, additionally, their offense was mostly stalled. And the bullpen that had been shaky in leverage delivered 5 1/3 strong innings from five relievers, sans a ninth-inning solo home run allowed by Emilio Pagan.

The bullpen’s 3.78 ERA ranks fourth in the Majors, its 544 strikeouts rank second and its 4.1 Wins Above Replacement rank fifth. But those numbers have taken a turn over the past month. After leading the Majors with a 3.36 ERA through as late as July 17, the collective staff’s 4.50 ERA entering Friday was 14th.

“We're aware of it, but I think everyone in this group is just focused on what they have to do to help the team,” Poche said. “And I think everybody has that kind of focus, and that's putting us in a good spot.

“A day like that, you've got to be prepared to go more than one inning. But we've got a lot of good pitchers in here. A lot of righties who can get lefties out. I'm the only lefty down there, but I'm not the only lefty who can get lefties out.”