What Happened to Paul Skenes?

After back-to-back sub-2.00 ERA seasons and the 2025 NL Cy Young, Paul Skenes is sitting on a 3.62 ERA through 18 starts. This dashboard digs into the pitch-level Statcast data for an explanation. The short version: the strikeout stuff is intact and his FIP says he's pitched closer to a 3.09, but he has already matched last season's full-year home run total in about half the innings, and the fastball has lost a tick.

3.622026 ERA, vs 1.97 in 2025

3.092026 FIP, so the gap is mostly sequencing and batted-ball luck

1.02HR/9, up from 0.53: 11 HR in 97.0 IP after 11 in 187.2

96.3avg 4-seam mph last start, vs 98.2 avg in 2025

The ERA says collapse. The FIP says two bad nights.

Cumulative ERA and FIP by start. Opening Day (5 ER in ⅔ of an inning against the Mets) left the ERA at 67.50 after one start, so the chart begins at start two. From mid-April to mid-June he ran an ERA between 2.36 and 3.00, then gave up seven runs in Philadelphia on July 1. Red dots mark home runs allowed: they cluster in exactly the starts where the ERA line jumps.

The home runs have a fingerprint

All 11 home runs, plotted where they crossed the plate. Almost every one is middle-in or middle-up, and 5 of 11 came off the four-seamer, the pitch he throws when he needs a strike. In 2025 hitters were late on 98-99. At 96-97, the misses over the plate are getting barreled instead of fouled off.

Xander Bogaerts · 04/07 · 4-seam fastball, 2-2 count, 105.3 mph off the bat
CJ Abrams · 04/13 · 4-seam fastball, 2-2 count, 104.6 mph off the bat
Jordan Walker · 04/30 · sweeper, 2-1 count, 107 mph off the bat
JJ Wetherholt · 04/30 · 4-seam fastball, 2-0 count, 107.7 mph off the bat
Bryce Harper · 05/17 · sinker, 1-0 count, 103.7 mph off the bat
George Springer · 05/23 · 4-seam fastball, 0-2 count, 106.8 mph off the bat
Joe Mack · 06/14 · changeup, 1-1 count, 102.3 mph off the bat
Heriberto Hernández · 06/14 · sinker, 2-2 count, 104.4 mph off the bat
Jake McCarthy · 06/20 · 4-seam fastball, 2-1 count, 104.9 mph off the bat
Brandon Marsh · 07/01 · slider, 1-0 count, 99.2 mph off the bat
Trea Turner · 07/01 · sweeper, 0-1 count, 93.8 mph off the bat

The arsenal, 2025 vs 2026

Whiff rate is down on nearly every pitch. The changeup and slider still miss bats; the sinker's whiff rate has collapsed from 15% to 8% and the splitter is getting hit at a .366 clip. The curveball, a real weapon in 2024, is basically shelved at under 1% usage.

Pitch	Usage	Velo (mph)	Whiff%	BAA	HR
4-Seam Fastball	38.4% -0.5pp	97 -1.2	27.0% +0.8pp	.188 -.017	5
Changeup	16.2% +5.3pp	88.8 +0.1	36.6% -6.2pp	.210 +.107	1
Sweeper	16.0% +0.2pp	84.2 -0.3	26.0% -5.1pp	.103 -.047	2
Sinker	11.7% +1.3pp	96.7 -0.9	7.5% -7.8pp	.267 +.047	2
Splitter	11.0% -2.5pp	93.5 -0.2	17.8% -3.1pp	.366 +.097	0
Slider	6.1% +0.5pp	86.7 +1.4	32.2% -1.6pp	.176 -.051	1

Usage and velocity deltas vs 2025. Green = improved, red = worse. Whiff% = swinging strikes per swing. BAA hidden under 10 at-bats.

The quiet warning sign: velocity

Average four-seam velocity by start. He opened the year at 97.9 and his last four starts have all been 96.9 or below, more than a full tick under his 2025 average of 98.2. Nothing here screams injury, but the trend is the one thing on this page that isn't explained by luck.

So what actually happened?

Three things, in order of importance. First, home runs: he has allowed 11 in 97.0 innings after allowing 11 in 187.2 all of last year, and they're concentrated on fastballs over the middle. Second, two disaster starts: Opening Day and July 1 account for 12 of his 39 earned runs; without them his ERA is near 2.9. Third, the stuff is a half-grade duller: velocity down about 1 mph and whiff rates down across the arsenal. Not enough to make him bad, but enough to shrink the margin for error that made 2025 look easy. The strikeouts are still elite, the walks are still stingy, and FIP thinks he's been a top-of-rotation arm all along. This looks less like a decline and more like a great pitcher having a normal season, with some bad timing mixed in.