Paul Skenes’ Sinker Is The Best Pitch In Baseball By A Wide Margin

For most of the last month in this space I’ve been unfurling my annual Best Pitches series. For all starters with 135 or more innings we’ve been grading out individual pitches that have met set total pitch and batted ball thresholds based on their respective bat-missing and contact management performances. This culminated in the calculation of Starting Pitcher Grade Point Averages.

Unfortunately, three of the most dominant starting pitchers in the National League did not reach the 135 inning mark. So we’re going to follow up by examining the pitch arsenals of the Pirates’ Paul Skenes, Dodgers’ Tyler Glasnow and Giants’ (now a Dodger) Blake Snell. First up, the young Pirate dominator.

Skenes threw six different pitches in 2024, but received only three individual pitch grades. His changeup and curve didn’t meet criteria necessary to receive one (we’ll talk a little about them later anyway), and his slider and sweeper were combined into one slider grade as consistent with my grading policy.

That leaves us with his four-seamer, sinker and slider/sweeper combo. We’ll dispense with the first and last of them initially. Both pitches receive a solid “B+” grade. He throws his four-seamer a healthy 39.2% of the time. Four-seamers are the least effective pitch in the game, but great pitchers tend to throw pretty good ones. Skenes’ is solid as a rock if somewhat unspectacular overall. Its pitch-specific whiff rate of 10.2% is about a half standard deviation above the qualifiers’ average, while its 109 Adjusted Contact Score (100 equals league average of all pitches, lower number the better, though the average four-seamer Adjusted Contact Score was 117.3 in 2024) grades out at the top of the league average range. Its score are almost identical to teammate Mitch Keller’s (110, 10.4%, “B+”). That’s a nice fastball, but not quite an elite one.

He threw his slider/sweeper combo (he threw the sweeper about twice as often) 16.2% of the time. While the “B+” grade is not particularly eye-catching, how he got there is quite notable. Its pitch-specific whiff rate was a relatively non-descript 10.8%. Contact management? A totally different story, as its 59 Adjusted Contact Score was nearly two full standard deviations better than league average, and better than all but two of the 65 slider grade qualifiers (Andrew Abbott and Hunter Greene at 47 and 52 – both received “A+” grades). Overall, Skenes’ slider was most comparable performance-wise to Zach Eflin’s (61, 10.2%, “B+”).

Then there’s the sinker. Skenes threw this pitch a healthy 28.4% of the time. 52 pitchers met the pitch/batted ball guidelines necessary to receive a grade. None of them had a pitch-specific whiff rate over 9.5% (Sean Manaea), and only four exceeded 7.0%. The standard deviation of all of the individual qualifier whiff rates was a mere 1.4%. Bottom line – the sinker is not a swing-and-miss pitch. The qualifiers’ average whiff rate was a lowly 5.0%.

Then there’s Skenes. His sinker whiff rate was an off the charts 15.9%. That’s over SEVEN AND ONE HALF STANDARD DEVIATIONS above league average. That’s beyond insane. On top of that, only five of the 52 qualifiers had a better pitch-specific Adjusted Contact Score than his 75. This pitch was an all-around lethal offering in 2024. There’s no other sinker it can be compared to, and really, no other pitch of any type that measures up even closely to it. I award extra “pluses” to “A+” pitches when appropriate – for example, Carlos Rodon’s changeup got an “A++” in 2024.

Using the same methodology, Skenes’ sinker deserves an “A++++++” grade. Six pluses.

Interestingly, the physical characteristics of Skenes’ sinker don’t stand out all that much. Its 94.0 mph velocity is in the average range, and its 1769 rpm spin rate and 0.7 in. vertical movement are quite low, though its 8.6 in. horizontal movement is above average. Its the way Skenes uses his sinker within the context of his overall repertoire that makes it so special.

Those extra pluses that I rarely do extend, however, are not factored into my pitcher Grade-Point Averages. Based on his individual pitch grades and their respective usage, Skenes’ 2024 GPA is an excellent 3.84, which would rank 5th among the 88 qualifiers, behind only Hunter Greene (4.19), Garrett Crochet (4.15), Zack Wheeler (4.06, with “A+” four-seamer AND sinker) and Shota Imanaga (3.87). Given the opportunity to inflate Skenes’ sinker grade to an appropriate level, he just might pass them all, and at least would certainly surpass Imanaga.

What about his other, non-qualifying pitches, the curve and changeup? I actually don’t have a ton to say about his curve. Its 12.6% whiff rate is ordinary, and it doesn’t have enough of a contact management track record to make any sort of long-term conclusion. He did post an otherworldly 29.8% whiff rate with his changeup – that’s higher than all 46 qualifiers. “A++” guy Rodon ranked 3rd among them at 25.5%. Skenes only threw his change 114 times, but that kind of whiff rate was no blip. He’s got another potential “A++” pitch lurking in the shadows.

So, what limitations, if any, do I see for Paul Skenes moving forward? About the only concern (beyond potential injury, of course), that I can see is the potential lack of a reliably plus breaking ball. Contact management performance is more volatile than bat-missing, so I can’t totally sign off on his slider as a true “A” pitch. This is basically the only concern I have for reigning AL Cy Young winner Tarik Skubal (his 3.58 GPA ranked 10th among qualifiers). The possession of an “A” breaking ball (sweeper) in addition to two dominant fastballs is why I place the Phillies’ Wheeler on another level above all of these studs.

But Skenes, unlike Wheeler, is not yet a finished product. He showed us plenty in 2024, and is set for a repeat command performance, this time from Opening Day forward. We’ll all be watching.