Prospect Scouting & Stats — Pitcher SwStk%

We’re winding down our look at pitching prospect scouting and stats, so today, I’ll present to you the leaders in SwStk%. While I haven’t seen any research to support my opinion, I feel like minor league SwStk% is a better indicator of future MLB strikeout rate than minor league strikeout rate. That’s because the ability to generate whiffs seemingly translates to the Majors better than called and foul strikes, the latter two strike types being more difficult to achieve with better competition. Whereas a whiff is a sign of dominant stuff and more pitcher controlled. Perhaps I’m wrong though. Either way, let’s check out the best minor league whiff-inducers.

Two years ago, I found that SwStk% marks are significantly higher in the Rookie league than all other leagues. So to make sure all SwStk% marks on the leaderboard are on a relatively similar playing field, I’m going to exclude pitchers who would have appeared, but the majority of their time was spent in that league in 2019.

And now, the top 8 pitchers in SwStk% (versus a league average generally in the 10%-13% range).

James Karinchak tops our board, having posted a ridiculous 23.1% SwStk%. But that SwStk% probably isn’t the nuttiest statistic from his 2019 line. That honor actually goes to his strikeout rate, which was an insane 59.2% across three minor league levels. On the back of that performance, he earned a callup to the Indians, where he continued where he left off in the minors over 5.1 MLB innings. This is a prime target in AL-Only leagues and he’ll earn value even if he fails to save one game.

Boy, Sam Delaplane can’t come up soon enough to help in the Mariners bullpen. With no clear cut closer, the team could certainly use a guy posting SwStk% marks over 20% and strikeout rates over 40%. With a 60 grade fastball and 70 grade slider, he seemingly has the stuff to back up the whiffs. He could make his debut quickly and is a nice darkhorse for saves.

Kevin Ginkel was a mini-Karinchak, shooting through three levels, striking out everyone in sight, before making his MLB debut with the Diamondbacks. However, Ginkel wasn’t nearly as dominant as Karinchak was after his promotion. That said, his slider was still fantastic, generating a SwStk% just over 20%, but the fastball was merely solid, and held back his performance from being more dominating. He also apparently throws a 55 grade changeup, but ended up throwing it just 1% of the time in the Majors. If it’s any good, I would imagine that throwing it some more should make him even more effective.

At age 26 now, having not sniffed Triple-A just yet, Dany Jimenez is a bit old given where he stands on the ladder, and his 2019 performance was apparently not good enough for the Blue Jays to keep, which is surprising. While he was pretty good previously, he really broke out in 2019, pushing his SwStk% marks above 20% and strikeout rates above 30% and 40%. With a 60 grade fastball and slider, it makes sense for the Giants to take a chance on him. And hey, given their uncertain closer situation, perhaps Jimenez eventually gets a shot to save games.

Bailey Ober’s strikeout skills actually surged after his promotion to Double-A, but that’s not actually the most intriguing thing about him. Instead, it’s his control, which has been elite throughout his minor league career. Amazingly, his highest ever walk rate at any one stop is just 3.4%. He posted an unbelievable 87:8 K:BB ratio between High-A and Double-A last year. It’s pretty surprising given that both his fastball and curveball are graded at just 45, while his changeup seems like the only above average pitch with a 60 grade. Perhaps the craziest fact when combined with his strikeout ability is that his fastball grades at 45 for a reason — it sits between just 85 and 87 MPH, topping out at a measly 88 MPH! Word is that he’s gotten by via deception, so naturally there’s skepticism as to whether he could replicate anything close to this kind of success if he reaches the Majors. He’ll be fun to folow.

Jackson Rees did see his SwStk% fall from 24.7% to 16.6% upon moving up from Single-A to High-A, but the lesser mark is still quite good. What’s exciting is that he paired it with a near 60% ground ball rate at the higher level, and a near 70% mark at the lower level. Tons of ground balls, strikeouts, and reasonable control? If he wasn’t already nearing 26 years old, I would be excited.

Brandon Williamson was just drafted last year and so we have just 15.1 Low-A innings from him. But those innings were darn good and makes us pay attention, as he struck out 41% of the batters he faced. None of his pitches stand out from a scouting grade perspective, though, so we’ll find out if it was just a small sample fluke or if his stuff actually plays better than it seemingly should.

It’s hard to get excited about a Rockies pitching prospect, but Tommy Doyle is trying his hardest. His SwStk% and strikeout rate has actually risen at each higher level, and he has also posted a ground ball rate over 50% at each of his three stints. Inducing grounders is one way to keep the ball in the park at Coors Field! He’s just a reliever though, but so far with improving skills, he could be in the closer conversation down the line.