Ranking the 4 best pitches on the Mariners’ 2025 staff

The 2025 season will likely mark another year where the Seattle Mariners will have to depend on their pitching to win games. After all, it only took two games before the lineup was shut out for the first time.

With pitching shaping up to be the biggest strength of the team, what are the best tools that they have at their disposal? Ahead, we rank the four best of the best according to certain categories.

Best Four-Seam Fastball: Bryce Miller

The four-seam fastball continues to be the most popular and effective pitch in MLB. Its movement profile isn’t particularly interesting, but its sheer focus on maximizing velocity is typically enough to dazzle fans day in and day out.

Logan Gilbert received the lion’s share attention for his performance in 2024 and his numbers were enough to ignite a serious discussion about a possible extension, but he may not have been the most valuable pitcher on the team. Purely on the basis of rWAR, Bryce Miller was actually the head honcho with of mark of 3.4 over Gilbert’s 2.8. Miller posted a 2.94 ERA over 180.1 innings, and his success was largely due to the quality of his heater.

It averages 95 mph with 18 inches of induced vertical break, an elite combination that gives his fastball plenty of rise. Opposing hitters averaged just .184 against it and whiffed 26.4% of the time, giving him a total run value of plus-19. With his shape, velocity, good command, the improvement of his fastball was a big reason the rest of his pitches were able to flourish.

Best Fastball Variant: George Kirby’s Sinker

George Kirby’s sinker has become the stuff of legend, especially when it comes to being executed with pinpoint command. Over his three big league seasons, he has a cumulative walk rate of just 3.1 percent.

Typically, those who rely heavily on sinkers aim to induce ground balls and keep everything in the infield. However, Kirby is a little different. He has alternated between using the slider and the sinker as his secondary weapon, but when he does use his sinker, he loves to paint the edges of the zone for sneaky called strikes rather than goading hitters into taking ill-advised swings.

Kirby will miss the first portion of the season due to shoulder inflammation, but it shouldn’t keep him out of action for too long. When he does return, the already star-studded rotation will be driven up yet another notch.

Best Breaking Ball: Logan Gilbert’s Slider

Something many fans may not have known is that over the past two years, Gilbert’s most effective pitch is not his fastball, splitter, or curveball. Instead, his slider is responsible for much of his success.

In 2024, it had a 36.8 whiff percentage and a .210 opposing average on the way to accumulating a run value of plus-16. By this metric, Gilbert had the fourth-best slider in MLB behind Dylan Cease, Chris Sale, and Ronel Blanco.

Any slider that averages nearly 89 mph with 35 inches of vertical drop will be difficult to hit, especially relative to the arm-side movement of his splitter. In his first start of the season against the Athletics, he actually threw more sliders than four-seam fastballs. His usage definitely won’t stay that way but it’s a testament to the confidence he has in that pitch.

Best Off-Speed: Bryce Miller’s Splitter

Over the past few years, the splitter has slowly but surely returned to vogue. Last year, Nathan Eovaldi, Tanner Houck, and Shota Imanaga were some of the best at using it. So was Miller, whose splitter run value of plus-eight placed him sixth in MLB.

However, he might be the future face of the pitch as his approach is particularly unique. In 2024, he held opposing batters to a .148 batting average with a 29 whiff percentage. The overall wOBA on his splitter of .174 was the lowest of any other tool in his arsenal by far. With 38 inches of drop and ten inches of arm-side run, it’s easy to see why.