Why the Pirates should still get some credit for developing Paul Skenes

The Pittsburgh Pirates are an organization on the rise, due in large part to their recent success developing young pitchers. Jared Jones had an impressive rookie season, and the club has Bubba Chandler, Thomas Harrington, and Braxton Ashcraft waiting in the wings as top-100 prospects.

It almost feels like cheating to lump Paul Skenes in that category—he just posted one of the best rookie seasons of all time, but he is so talented that he would have thrived no matter who took him No. 1 overall in 2023. But he's far from the same pitcher who sported a 1.69 ERA and 209:20 strikeout-to-walk ratio in his final season at LSU.

Skenes was essentially a two-pitch pitcher in college, because that was all he really needed. He put himself on the map with a fastball that routinely hit triple digits and a devastating wipeout slider, only very seldom mixing in a changeup. While he was a can't-miss prospect, there were some questions as to how quickly and effectively he'd be able to expand his repertoire in order to become an established MLB starting pitcher. The Pirates were more than up to the task.

The Pirates helped Skenes make changes to his pitch mix, elevating him from one of baseball's best prospects to one of baseball's best pitchers.

Skenes was utterly dominant in his first season at the sport's highest level, and he did this in part by throwing the single greatest pitch among all starting pitchers. But here's the catch—it wasn't his fastball or his slider, the two pitches that got him to this point. It was the dreaded splinker.

The sinker-splitter hybrid is perplexing to both the guys trying to hit it and the folks tasked with classifying it—upon Skenes debuting the pitch, Baseball Savant initially considered it a split-finger, but after Skenes himself referred to it as a sinker, they followed suit. Call it what you want; the pitch is downright nasty.

Opponents batted just .184, slugged .234, and whiffed on nearly 30% of swings against Skenes' splinker. All that culminated in the offering's Run Value, estimated by Baseball Savant as 2.99 runs per 100 pitches, ranking as the best pitch thrown at least 500 times by any starting pitcher in 2024. Expanding that list to include relief pitchers, the pitch trails only Cade Smith's fastball and Emmanuel Clase's cutter.

The pitch's success stems from how unique it is; its combination of velocity and movement is virtually unmatched. Other split-finger pitches with similar movement profiles are thrown much slower than Skenes', and the only one with a higher average velocity trails considerably in both vertical and horizontal movement:

Not only has Skenes added a devastating new pitch to his arsenal, but he has also added to the overall quantity of his pitch mix. His slider is now classified as two separate pitches: his traditional sweeper and a more cutter-like slider. The two pitches are separated by approximately two miles per hour and 10 inches of glove-side movement.

As the season progressed, Skenes increased his usage of a new curveball and a changeup, with great results. The curveball became his primary breaking pitch in some outings, which kept hitters on their toes and increased the effectiveness of his sweeper and slider. A pitcher of Skenes' caliber having multiple plus breaking pitches running in different directions is unfair.

His changeup was somehow even better. It was his least-thrown pitch throughout the season, but he increased its usage in September (13.6% in September vs. 3.5% through August), and it became a real weapon. Opposing hitters batted just .048 (with zero extra-base hits) and posted an unfathomable 69.7% whiff rate against his changeup in September, and that coincided with his best stretch of the season—Skenes recorded a 0.75 ERA, 1.21 FIP, and 34:6 K:BB ratio in 24 innings to end the season.

What's more, while Skenes' pitches were extremely effective across the board, most of them actually underperformed according to their expected metrics:

Paul Skenes with two pitches was a pretty darn good pitcher. Paul Skenes with six pitches is a cheat code. He has developed the ability to manipulate a baseball in whatever direction he wants, to locate a baseball wherever he wants, and to throw any of his pitches in any count he wants.

The Pirates' recent track record with developing young pitchers has come into play with Paul Skenes.

FanGraphs' final scouting report on Skenes notes that the Pirates "gave Skenes some very specific developmental boxes to check" before he joined the big league rotation and that "the rate at which Skenes has learned some of these new tricks...is very exciting." While that obviously entails much more than just his pitch selection, that has undoubtedly played a significant part in his development.

The Pirates knew they had an exceptional talent on their hands, but also knew exactly what needed to occur to enable Skenes to take the next step. He has already taken MLB by storm and become just the second Rookie of the Year winner in franchise history. Pittsburgh hasn't seen a division title or a Cy Young Award winner since the early 1990s—he has a chance to end those streaks as well.