What's Actually Wrong With Paul Skenes: His Sinker and Splitter, Not His Stuff

I’m tired of writing about Paul Skenes. But until we figure him out in 2026, we press on.

Skenes is still striking hitters out at one of the best rates in baseball. That single fact should end most of the panic around his rising ERA before it starts, because a pitcher who has lost his stuff does not keep missing bats at an elite clip. What Skenes has lost is command, and specifically the two pitches that depend on it most: his sinker and his splitter. This is not a broad decline. It is a two-pitch problem hiding inside an otherwise excellent arsenal, and the data tells you exactly where to look.

The Strikeouts Never Left

Run the numbers month by month and the strikeout rate is the one thing that has not moved in the wrong direction. Skenes struck out 30.6 percent of hitters in April, 29.5 percent in May, and 33.1 percent in June, with his K/9 sitting north of 11 for the season through June. That is not the signature of a pitcher whose stuff has degraded. Velocity, spin, and swing-and-miss ability are still fully present.

This distinction matters for how you read the rest of this piece. A pitcher who is missing bats at an elite rate but bleeding runs is a specific, recognizable pattern: something in the delivery of the pitch, not the pitch itself, has broken down. Command and sequencing problems produce exactly this signature. Stuff decline does not. Once you see the strikeout rate holding steady, you already know where the investigation needs to go.

The Walk Rate and Exit Velocity Tell the Real Story

The walk rate is where the season actually turns. Skenes walked 4.0 percent of hitters in April and 4.1 percent in May, both comfortably above-average marks. In June that number jumped to 6.8 percent, and the exit velocity allowed climbed alongside it, from 86.7 mph in April to 87.8 in May to 89.8 in June. Hitters are doing more damage on contact at the same time Skenes is missing the zone more often.

Source: FanGraphs monthly pitcher leaderboards, April through June 2026.

The shape of this decline looks mechanical rather than situational. A pitcher who is simply getting unlucky does not see his own walk rate and the exit velocity against him rise together in the same month. Both numbers point at the same root cause, which is that specific pitches are no longer landing where he wants them.

The Specific Problem: Sinker and Splitter

This is where the month-by-month pitch data becomes the whole story. Skenes has not stopped throwing his four-seamer or his slider, and both pitches remain effective; usage on both has actually climbed as the season has gone on. What has collapsed is his sinker and his splitter, both in how often he throws them and in what happens when he does.

Source: Baseball Savant pitch-type usage, FanGraphs monthly exports.

The run-value trend on those two pitches is the clearest evidence in this entire piece. His sinker was a plus pitch in April and May, then cratered in June. His splitter followed a similar arc, dipping negative in May before June's tiny sample muddies the read.

Source: Baseball Savant, run value per 100 pitches. Positive values favor the pitcher.

The four-seam soared in total usage as well, with those two pitches counting for more than 71 percent of his total June offerings. That has to change in July. When two of your five pitches stop working, the other three get more predictable, and hitters get more selective. A realistic path back for Skenes runs through rebuilding the sinker's command specifically, not through throwing his fastball harder.

What the xERA Gap Actually Means, and the Competing Explanation

Skenes carries a 3.62 ERA against a 2.75 xERA, and that gap tells you some of this is bad luck layered on top of the real decline. The strikeout-and-walk profile alone would predict a lower ERA than he currently has, which is the standard signal that some correction is coming regardless of what happens with the sinker and splitter specifically.

The fantasy math is straightforward from there. The part of the gap that is pitch-mix-fixable will close once the sinker and splitter command returns, which is the kind of adjustment pitchers this talented tend to make within a matter of starts, not months. The part that is defense-and-luck-driven will close on its own schedule and is out of Skenes' hands entirely. Neither path requires you to sell a pitcher who is still striking out a third of the hitters he faces.

Paul Skenes is not broken. He is a pitcher whose two hardest-to-command pitches stopped working in the same month his walk rate spiked, and the strikeout rate that makes him a first-round arm has not budged. Hold him through the correction. The sinker and splitter are the two things worth checking on Baseball Savant every week for the rest of the summer, because when those run values turn positive again, the ERA will follow the xERA down.

Questions About Paul Skenes, And Some Answers

Why has Paul Skenes' ERA gone up so much in 2026?
His rising ERA is not the result of diminished stuff. His strikeout rate has remained elite while his walk rate increased and both his sinker and splitter posted significantly worse run values during June, leading to more damaging contact and poorer overall results.

Is Paul Skenes still a good fantasy baseball pitcher?
Yes. His underlying strikeout ability remains intact, and his 2.75 xERA sits well below his 3.62 ERA. That combination suggests better results are still possible if his command, particularly of the sinker and splitter, improves.

What pitch is causing Paul Skenes' struggles?
The biggest issues have come from his sinker and splitter. Both pitches have seen reduced usage and sharply worse run values as the season has progressed, while his four-seamer and slider have remained effective and made up a larger share of his repertoire.

Is Paul Skenes' decline due to bad luck or bad performance?
It appears to be a combination of both. His xERA indicates some poor fortune has inflated his ERA, and Pittsburgh's defense has also been cited as a contributing factor. At the same time, his walk rate and the quality of contact against his sinker and splitter have both worsened.