The New Pitch Fueling Connor Prielipp's Success

[Sam Caulder]

Image courtesy of © Bruce Kluckhohn-Imagn Images

There are few pitchers in the Twins' organization whose raw stuff can match Connor Prielipp's. Ever since his freshman season at the University of Alabama, it was obvious the left-hander possessed the upside of a frontline major-league starter. Injuries altered that path considerably, but now that he's finally healthy and pitching in the big leagues, we're getting a better look at what his arsenal actually looks like against major-league hitters. And thanks to Statcast's new swing timing data, we're also getting a better idea of which pitches are working, and which ones aren't.

At first glance, Prielipp's overall whiff rate doesn't look particularly impressive. His 22.2% mark would rank in just the 28th percentile among major-league pitchers, hardly the profile of a dominant swing-and-miss arm. But part of being a young pitcher is figuring out what plays at the highest level. The pitches that made you successful in college or the minor leagues aren't always the ones that generate the best results at the highest possible level of competition. For Prielipp, that learning process has been fascinating to watch unfold.

Let's start with the fastball. Coming through the minors, Prielipp's fastball-slider combination was viewed as the foundation of his arsenal. The slider earned 70-grade projections from scouts, while the fastball's velocity and characteristics gave hitters plenty to think about. While the slider has largely held up, the fastball has been a different story.

Interestingly enough, the swing timing data isn't entirely negative. Hitters have been late against Prielipp's four-seamer at times, suggesting the pitch still has enough life to disrupt timing. The problem is what happens when they actually connect. Opposing hitters own a .558 slugging percentage on fastballs put in play, and the pitch has generated just a 14% whiff rate. That's the lowest mark among his entire arsenal. Hitters aren't consistently missing the pitch, and when they do make contact, they're doing damage.

That's shown up in the batted-ball profile as well. A significant portion of the hard contact Prielipp has allowed this season has come against the fastball, which has tended to play more as a fly-ball pitch than a true bat-misser. It needs to be that, too, because based on the way hitters are centering the ball on the barrel (in the left-hand image), they're going to hit it hard when they connect. (Centering the ball on the barrel controls exit velocity more than lining it up vertically or timing it perfectly.)

The good news is that Prielipp hasn't relied on the fastball as a put-away pitch. That's where the breaking balls come in. His slider remains a weapon. Hitters are whiffing on roughly 28% of their swings against the pitch, and the swing timing data paints a pretty clear picture of why. Opposing hitters are frequently early and have given some ugly swings, off in multiple dimensions. It's still every bit the plus pitch scouts thought it could be.

But oddly enough, it may not even be his best breaking ball anymore. That distinction belongs to the curveball. Added to his arsenal ahead of the 2026 season, the curveball has quickly emerged as one of the most effective pitches he throws. Hitters are whiffing on 34.4% of their swings against it, making it his best swing-and-miss offering by a comfortable margin.

The swing timing data is even more encouraging. Unlike the fastball (which hitters occasionally square up despite being late) or the slider (which they're often way off on, but which they also meet perfectly surprisngly often), opposing hitters look completely uncomfortable against the curveball. They're frequently committing too early, swinging over the top of it, and generating exactly the kind of ugly swings pitchers love to see. Quite frankly, it's been a better pitch than the slider, which is saying something.

The underlying characteristics help explain why. Prielipp's curveball is averaging nearly 3,200 RPMs of spin, a truly elite number. Not only is it generating more whiffs, but Prielipp has increasingly trusted it in put-away counts as the season has progressed. That evolution has become evident in his pitch usage.

Early in the season, Prielipp leaned heavily on the slider. In his first couple of starts, he threw it more than 50% of the time, while the curveball accounted for less than 10% of his pitches. Those numbers have since gradually converged. In his most recent start, he threw only one more slider than curveball, and it’s hard to imagine that’s a coincidence. Pitchers adjust based on results, and right now the results are telling Prielipp that his curveball deserves a larger role.

None of this means the fastball can't improve, nor does it mean the slider has taken a step back. Both pitches have shown flashes of being highly effective major league offerings. But if the swing timing data is telling us anything, it's that Prielipp may have discovered something even better. If he can consistently throw the curve for strikes (or for convincing strike-to-ball chases), it might be the most lethal arrow in his quiver.

He was already a fascinating pitcher with a fastball-slider combination capable of overpowering hitters. Now he's pairing those pitches with a curveball that has quickly become one of the nastiest offerings in his arsenal. And if that pitch continues to perform the way it has so far, the path to becoming a frontline starter becomes a whole lot easier to envision.

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[DataNerd]

If Prielipp had a normal development path, he probably adds a curveball his So or Jr year of college.  The advantage of taking high spinrate pitchers is that they often are able to just add a good, or in this case elite, pitch from scratch.

[twinstalker]

Prielipp is super interesting.  At first glance, and it may be the right one, he doesn't have a pitch to get rh batters out.  This is beyond my scope, really, but it would seem he needs a changeup ( a good one), a cutter, or a splitter to get out right handers.  Most pitchers are going to eventually groove their breaking ball to opposite sided hitters, and that's where one asks if his slider and/or curve are going to be consistently better (as described) than almost all the pitchers' in MLB.  It's a fear that it won't be, but he's been impressive thus far.

Question:  how many more (non-opener) starter innings does Prielipp get this year?  My thought is he should take a long break while the Twins have five other starters and start back again after trade deadline.  Is 110 ip the max overall?  Do you let him get to 100 ip and use him in relief for 10-20 innings to close the season?

[DataNerd]

30 minutes ago, twinstalker said:

Prielipp is super interesting.  At first glance, and it may be the right one, he doesn't have a pitch to get rh batters out.  This is beyond my scope, really, but it would seem he needs a changeup ( a good one), a cutter, or a splitter to get out right handers.

Often curveballs are just as good against opposite handed hitters, and sometimes even better than same.  It's currently SSS, but he has a significantly higher whiff rate against RHH (38.6%) vs LHH (23.5%), and it has had a positive run value against RHH and negative against LHH.

His slider has also been above-average to RHH.  The main problem is that fastball has been awful to them.  Poor extension takes off about 1mph from the fastball, and it doesn't have good movement.