SI:AM | The Numbers Behind Paul Skenes’s Stunning Dropoff

Good morning, I’m Dan Gartland. I’ll be honest. I expected Paul Skenes would have a lousy start last night, so I wrote most of this yesterday afternoon.

In today’s SI:AM:
😬 Skenes’s struggles
⛰️ USWNT captain’s homecoming
🏈 Vikings name their starting QB

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What’s wrong with the reigning Cy Young winner?

Something is up with Paul Skenes.

Skenes lasted just five innings in his start last night against the Marlins, allowing two runs (one earned) on five hits, with four strikeouts, one walk and one hit by pitch. The Pirates went on to lose, 2–0, and are now 58–63.

It was the latest in a series of disappointing outings for Skenes, who allowed 13 runs and 10 walks in his previous three starts while pitching 14 ⅓ combined innings. The former No. 1 draft pick, who had blown hitters away from the moment he reached the majors in 2024, has suddenly looked shockingly mortal this season. He’s been markedly worse by almost every metric.

What jumps out most about Skenes’s results this season is that he’s laboring to get through just a few innings. He didn’t regularly go deep into games in his first two seasons, but that was because the Pirates were trying to protect his arm. This year, he’s getting pulled early because he’s already thrown what would be a full start’s worth of pitches for any pitcher. In seven of his last nine starts, he’s failed to finish six innings, and in four of those seven short starts he still threw more than 90 pitches.

At the start of the season, Skenes looked every bit like the pitcher who cruised to last year’s NL Cy Young award, posting a 1.98 ERA in his first nine starts. That even includes his bizarrely disastrous Opening Day performance against the Mets in which he allowed five runs and failed to get out of the first inning. If you throw that one out, in eight starts between April 1 and May 12, Skenes had a minuscule 1.09 ERA.

But Skenes has struggled mightily since then. He has a 5.00 ERA in his last 16 starts and has averaged roughly 5 ⅓ innings per outing while still throwing 95.6 pitches per start.

The obvious question is why, and there’s one glaring difference between this year and his dominant first two seasons: Skenes isn’t bringing the heat like he once did. In 2025, he averaged 98.2 mph with his four-seam fastball and 97.6 mph with his sinker. This year, the sinker is down almost a full mile per hour (96.7 mph), and the four-seamer has slowed even more (96.9 mph). In the 2024 and ’25 seasons combined, he threw 1,552 pitches at 98 mph or faster, more than any player in the majors. This year, he’s only thrown 97 pitches at least that fast, which ranks 72nd. He’s gone from throwing 30.3% of his pitches at least 98 mph in his first two seasons, to just 4.3% this year.

Last night, Skenes’s fastball topped out at just 96.5 mph. In his first two seasons, only 2.8% of the four-seamers that Skenes threw were that slow. This year, it’s 36.9%.

But it isn’t the fastball that has been hurting Skenes this season—at least not directly. The velocity has dropped, but the results of the pitch are perfectly fine: He ranks in the 85th percentile in fastball run value. It’s Skenes’s offspeed stuff that has been the bigger culprit. In his first two seasons, Skenes ranked at or near the top of the league in Statcast’s offspeed run value metric (100th percentile in 2024, 98th percentile last year). This year, he ranks in the 13th percentile. In other words, hitters are teeing off on Skenes’s changeup and splitter after being baffled by them in previous seasons. The decline in the effectiveness of Skenes’s fastball might partially explain why his offspeed stuff isn’t fooling anyone. While he’s throwing his heater slower this season, his changeup velocity is unchanged. The change simply can’t be as effective if it isn’t as deceptive.

The underlying reason for Skenes’s dropoff is still a mystery. It’s inevitable to wonder if he’s bothered by some minor injury that’s troublesome enough to impact his performance but not severe enough to warrant a trip to the injured list. (Pirates manager Don Kelly said after Tuesday’s game that Skenes’s early exit wasn’t due to an injury, but also said that “guys in August aren’t 100%.”)

Perhaps his workload is catching up to him. He threw 187 ⅔ innings last season, the most of any pitcher 25 or younger. Then he followed that up by participating in the World Baseball Classic. He only made two starts in the preseason tournament, but we’ve heard other pitchers express concern about making full-effort appearances before the end of spring training. Or is it his conditioning? Pittsburgh radio host Dan Zangrilli, who anchors the pre- and postgame shows for Pirates games, said late last month that he thought Skenes looked “out of shape.” I even saw Pirates fans on social media dissecting images of Skenes to determine whether his backside looked plumper in 2026 than in his Cy Young season, which tells you something about the lengths fans are going to in an effort to diagnose Skenes’s struggles.

The root cause may be unclear, but it’s evident that whatever’s bothering Skenes has led to a change in his mechanics. Tom Verducci has an excellent breakdown of how Skenes has changed his delivery, and how it’s having an especially significant impact against righties.

Whatever the reason for the decline, Skenes’s rather pedestrian season is a serious disappointment for the Pirates. They entered the season hoping to snap a decade-long playoff drought, and as recently as two weeks ago they were in position to make a real run at a postseason berth. But they’ve gone 3–11 since July 27 and gone from being tied for the final wild-card spot to being six games out. It’s easy to wonder how different things might be for the Pirates if they weren’t 9–16 this season in games started by Skenes.

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The top five…

Everson Pereira makes a catch at the wall — Jeff Curry/Imagn Images

… things I saw last night:
5. Yankees rookie George Lombard Jr.’s quick reaction to field a ball with his bare hand after it bounced off the base.
4. A really tough bucket by Kelsey Mitchell in the Fever’s win over the Liberty. Mitchell finished with 28 points and is second in the WNBA with 24.3 points per game.
3. An absolute rocket of a goal by Boca Juniors winger Leonel Flores in the Copa Sudamericana.
2. Pete Crow-Armstrong’s laser beam home run that left the bat at 111.5 mph and clanged off the facade of the upper deck at Nationals Park.
1. Cardinals center fielder Everson Pereira’s leaping catch while in an all-out sprint.

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