How the Mariners beat Tarik Skubal three times — and can they do it again?

Even the best pitchers in baseball lose games occasionally. Just ask Tarik Skubal. I’m sure you’ve read this a hundred times by now, but the Mariners have won all three games this year in which Skubal was the opposing starter. Seattle was the only team to hand him multiple losses in the regular season, and less than a week ago the Tigers lost in Game 2 of the ALDS — technically, Skubal didn’t get a decision. Now, with his team pulling off a comeback win in Game 4, Skubal is ready to start tonight’s decisive Game 5, giving him a chance to finally beat the Mariners this year.

I’ll be forewarned: This article will rely heavily on in-game statistics for hitters and pitchers; we’ll be examining some extremely small samples. But I thought it was an interesting investigation into the strategies that unfolded between familiar foes in a short playoff series.

What I really want to know is if the Mariners have a special formula that allowed them to be so successful against Skubal this year. As I mentioned, Skubal faced the Mariners twice during the regular season. On April 2 in Seattle, he allowed three runs in 5.2 innings; he gave up six hits and three runs while striking out eight. He faced them again in Detroit on July 11, allowing four runs in five innings; he allowed just four hits and two walks while striking out five. Last Sunday’s start in Game 2 was his best yet: He gave up two runs on five hits in seven innings, walking one on four walks, while striking out nine. Jorge Polanco’s two home runs were his undoing.

Of the Mariners’ current leadoff hitters, only Eugenio Suarez and Josh Naylor have failed to have a hit against Skubal this year; they’ve only faced him during the ALDS because they weren’t with Seattle earlier in the season, and Skubal has never faced the Diamondbacks. Polanco hit two home runs on Sunday, and Julio Rodriguez blasted a home run in July that was his only hit in 2025 against Skubal. Shockingly, JP Crawford has three hits this season with Skubal, tying him with Polanco for the lead.

If we look beyond the tiny sample of individuals and see how teams approach him, what will we find? Here’s how the Mariners performed against each of Skubal’s pitch types:

Skubal’s two best pitches are his four-seam fastball and his deadly changeup. Seattle’s hitters really struggled against Skubal’s heater, and their wOBA was abysmal, with just a 10% hard-hit rate. In fact, relative to league average, this year’s team has struggled against fastballs with velocity over 97 mph; the Mariners have a WOBA of 0.286 (league average is 0.295), an RV/100 of -0.75 (-0.61), and a whiff rate of 29.6 percent against hard material (23.7 percent). Skubal’s fastball is a top-tier pitch, better than any other starter’s pitch, according to Stuff+ , so it’s no surprise they’re difficult to work with from any authority.

What’s really surprising is how well they perform against Skubal’s changeup and slider. His changeup is arguably the best in baseball in 2025 — he leads all pitches with 25 runs scored, according to Baseball Savant. Even though the Mariners swung the ball around half the time he changed the ball, they actually did some damage on the field. Rodriguez’s home run in July came on a hanging changeup with the score 1-2:

Then there are sliders. Skubal’s breaking ball is the worst of his pitches, although it’s still above average according to Stuff+ ratings. Back in April, Dylan Moore, no longer with the Mariners, poked a backdoor slider over the right-field wall for an opposite-field home run. Most recently, Polanco hit a home run off a slider in July, and his first home run in Game 2 came off a hanging breaking ball:

Is there something about the Mariners’ approach to Skubal that would allow them to hone in on his secondary offer? Here are their key plate discipline metrics against him, broken down by pitch type. His full-year 2025 pitch types for each metric are broken down in brackets for reference:

Most notable was the Mariners’ refusal to chase Skubal’s changeup out of the zone. In 2025, he had a chase rate of nearly 50% in that game, but the Mariners only had a chase rate of 34%. He even noted what Polanco did after Game 2:

“[Polanco] It seems I see the ball very clearly. He made some changes and here they are [the zone]. Generally speaking, when I throw it out there and execute, it works out well for me. ”

Not only do the Mariners spit on changeups that come out of the zone, but they are more aggressive than other teams in the league on changeups that land in the zone. When they managed to force Skubal into the area, they were able to do some damage. They’ll also be patient enough to go for walks if Skubal refuses to pitch in the zone; Seattle leads all teams with six walks to Skubal this year.

Knowing how Seattle hitters have approached him in the past, I’m sure Skubal and battery mate Dillon Dingler are making plans for Game 5. Here’s his pitching mix against them so far:

From April to July, Skubal changed his pitching mix, adding more sinkers and sliders. In Seattle’s postseason starts, he changed gears again and used less of a changeup, no doubt understanding the Mariners’ patient approach to his slower stuff. Friday’s plan won’t be too different from the norm that Skubal has already set, but I’m sure it will have some issues. After Game 4, Dingler hinted at the stability of the game plan:

“We’re not going to stray too far from what he’s really good at. We’re not going to venture too far. We’re going to add off-speed, we’re going to add a fastball, we’re going to add a slider or a changeup just to get us to the finish line.”

Based on the approach the Mariners have shown in the first three games, perhaps Skubal will focus more on his four-seam fastball and allow the Mariners to dare hit his hardball. Maybe Seattle’s hitters will work on hitting their fastballs on Thursday’s off day. All of these game plans will be tested once the pitch starts flying tonight.

Another angle of analysis I would like to explore is to see if starting pitchers receive any penalties for making multiple starts in a playoff series. Just like relievers lose effectiveness the more often they play against the same opponent in a short period of time, starting pitchers can suffer similar negative effects on their second start. When hitters become familiar with the way a pitcher’s pitches move, they are better able to master those pitches. This is the same concept that reinforces per-order penalties.

I sampled every pitcher who has made multiple starts in a single playoff series since 2021, resulting in a sample of 54. I then calculated the difference in their performance from their first start to their second.

On average, across the four metrics I used, pitchers performed worse in their second starts; their ERA went up by nearly two points, their FIP increased by more than one point, their wOBA allowed 21 more points, and their strikeout-minus-walk rate dropped by two points. I also calculated the same performance difference, but removed the second launch taken during a short rest to control for potential fatigue effects. Even limiting the data to normally rested pitchers, we find that they performed worse in their second starts in a playoff series, although the effect was less dramatic; their ERA was up 1.07 points, their FIP was up 1.51 points, their wOBA allowed was up 17 points, and their K-BB% dropped 2.3%. Not only will Skubal be making his fourth start of the year against the Mariners, but the numbers suggest he may be penalized for recent facings against the Mariners.

We only have to look back to last year to see how Skubal performed in the decisive Game 5 after starting earlier in the series. Skubal had a solid performance in his first game of the 2024 ALDS against the Guardians. He pitched seven scoreless innings, allowing just three hits and striking out eight. However, Cleveland defeated him in Game 5, scoring five runs on a fifth-inning Lane Thomas grand slam, ultimately losing to Skubal 7-3, and Detroit went home for good. Pointing out last year’s Game 5 failure doesn’t necessarily portend a repeat tonight. Skubal has been one of the best pitchers in baseball for two years, with quality that exceeds most of the samples above, so any loss of familiarity may not be as significant as the data predicts. The Tigers are certainly confident in their ace.

Ultimately, Skubal’s success tonight will come down to execution. Will he make the necessary adjustments to keep Seattle’s hitters off-balance, or will they continue to be patient with a familiar foe and beat him for the fourth time this year?