SEATTLE — Bryce Miller has been in the big leagues for only 15 months, but because of the personality he’s brought, the evolution of his arsenal, and just as much, how consistently he posts, it can sometimes feel like he’s been here much longer.

The 25-year-old carved his way through the playoff-hopeful Mets on Friday night, twirling six shutout innings and scattering three hits and a walk to lift the Mariners to a 6-0 victory. He was backed by just enough offense early, first by a two-run homer from Ryan Bliss and then by a four-spot after he departed in the seventh when Leo Rivas and Cal Raleigh each ripped two-run singles.

Though the Mariners were mostly quiet at the plate until late, their insurance rally extended their MLB-best record to 38-4 when plating at least five runs — a stat that speaks to how successful they can be if they’re able to back their pitching staff. Miller and the rest of the Mariners’ arms collectively have a 2.81 ERA at T-Mobile Park this season — by far MLB’s best home clip, well ahead of the second-best Cubs’ of 3.24.

Moreover, Seattle needed to win on Friday to remain tied with Houston atop the American League West. And the club did so on the shoulders of its second-year starter, who has seen a second-half surge.

“It’s great to see a young pitcher like that at this time in the season have so much in the tank,” Mariners manager Scott Servais said. “Because we’ve got so many big games ahead of us.”

Overwhelming with offspeed
Utilizing seven different pitches, Miller mixed things up as much as he has all season — and, really, for his entire career, given that he’s still so young. Per Statcast, he threw a four-seamer, sinker, slider, splitter, knuckle curveball, sweeper and cutter on Friday — a massively far cry from the repertoire he possessed upon being first called up last May, when he was almost exclusively throwing heaters.

The diversification has been well-chronicled, from adding a splitter last offseason to tinkering with multiple variations of his slider since last summer. But it’s the curve — which he added ahead of a June 29 outing vs. Minnesota — that has really opened things up.

“He’s got another pitch that he can tunnel off his fastball,” Servais said before the game. “The velocity of the pitch, the depth of the pitch, he’s getting some chase on it below the zone. It’s worked really effectively for him. He needs to continue to throw it.”

The heater is still hot
Miller’s high-riding four-seamer still remains arguably his best pitch, even if it’s not as prominent given his new toys. Entering Friday, opponents were hitting .192 and slugging .345 against the pitch this season — including .160 and .320, respectively, since the All-Star break. Then, the Mets went 0-for-7 against it Friday, with two of his six strikeouts.

More telling, though, is that Miller appears to still be rising in velocity. The four-seamer saw a 0.6 mph jump on Friday and the sinker was up 0.7 mph. All of his pitches saw an uptick, but the fastballs are obviously the most notable — especially that the season has reached the dog days.

“Last month, I felt like I was kind of at a low point,” Miller said of his fastball. “And then the last couple weeks, it’s felt like it’s come back. At this point in the year last year — like, innings wise — I think I was just steadily going down, and right now I feel like I’m getting better.”

Working like a workhorse
Despite this being only his second season, and even though Servais pulled Miller after 87 pitches in a by-design effort to save his arm down the stretch, Miller appears to be capably handling the rigors of his first full MLB season.

On Friday, he surpassed his 2023 Major League innings total of 131 1/3 and is now at 132 2/3, over which he’s carried a 3.46 ERA. Yet across his past seven starts, dating to the outing when he installed the curve, he has a 2.45 ERA — and the Mariners have gone 5-2.

“Last year, I was getting fatigued at this point,” Miller said. “And last year, the fastball was my pitch. So, like, if that’s my pitch — and I’m fatigued — then it’s just like everything is kind of down. But this year, I feel like I’m getting better, getting stronger as the year goes on.”

These final seven weeks will define Seattle’s season — and Miller looks like he could be a huge contributor down the stretch.