Taking Another Look at Jonathan Bowlan

There is a repeated adage that teams are generally populated by smart people and when they make a puzzling move you should probably take a second look at it and see what the team saw and why they did it. When the Phillies acquired Jonathan Bowlan for Matt Strahm the general consensus was that it was a great move for the Royals and if you liked the deal it was more about Strahm being in decline and Bowlan being interesting in small sample. On the surface that take is probably enough to like the deal, but it turns out that is really getting to half a conclusion by not really doing any of the work and just making a guess.

In the most recent episode of his podcast For All You Kids (nominally a Mets podcast, you have been warned), Jarrett Seidler of Baseball Prospectus talked about being shocked by the backlash to the deal because Bowlan had certain pitch traits and outcomes that were elite. The consensus among people he talked to in the industry is that the Phillies had done extremely well in the deal.

Rather than start at Jarrett’s conclusion, lets start at the beginning and reexamine the player. I started with Rob Orr’s website and went to Bowlan’s individual pitches in the majors. Rob’s stuff model (Pitch Quality) rates out Bowlan’s changeup and slider well, and that both suppress damage. Bowlan’s fastball rates out ok for fastballs, but got hit around (something I latched onto in my initial assessment). The movement on the fastball is just ok too. It has 16.8″ of vertical break and 8.3″ of armside run, which isn’t bad but it also isn’t outlier. Same with the attack angle or 4.54 degrees. Having seen all of that, I glossed over the numbers that Jarrett latched onto, which is his fastball had a 22.1% swinging strike rate and 62.7% zone-contact rate.

To put those into context, Rob’s site conveniently has a percentile view. Here is how Bowlan’s fastball rates out. I have included chase rate and CSW (a combination of percentage of pitches that are either called a strike or are swinging strikes)

Swinging Strike	Z-Contact	Chase	CSW
100	99	92	99

A good fastball does not equal a great pitcher on their own, but those are elite outcomes on his fastball. He also does not throw it in the zone much (13th percentile) while not having it be a ball (63rd percentile) which is the secret sauce of command where it isn’t about throwing it in the zone, it is about inducing strikes.

So how is this happening if the movement traits all look solid, but unspectacular? The public smart knowledge on good 4-seam fastballs tends to be flat angles generated by low release points and often good extension to get to that release point. The amount of actual rise on the fastball takes second seat to how flat it is, especially up in the zone. We also know, and in the public generally worse at contextualizing, that the unexpected is better. Hitters don’t have every pitch movement memorized, but they have a pretty good feel for what a pitch looks like out of hand given arm angle, release height, and other contextual factors. It is why tunneling is important because if you can make two different pitches look that same out of the hand that gives the hitter problems.

We are going to use 4-seam fastball whiff rate going forward as our sorting tool because Baseball Savant makes it an available column. Among pitchers with at least 200 4-seam fastballs in the major leagues, Jonathan Bowlan ranks #1 in whiff rate (43.5%). Among pitchers with at least 150 fastballs thrown in the minors in a Statcast tracked game (so really AAA and Florida State League), Jonathan Bowlan ranks #1 in whiff rate (41.1%). Most of the leaderboard have low arm angles, release heights, or good extension (as we expected). Also as expected we see velocity start to dominate on this list as well.

In an effort to find some like minded traits I decided to use arm angle to pull out our sample and went with 30-45 degrees, to not include anyone going completely over the top, and then limited it to RHP with a whiff rate >30%. (note there are some measurement differences between Rob and Savant so are comparing like to like)

Whiff%	IVB (in)	HB (in)	Velocity (mph)	Release Height (ft)	Extension (ft)	Angle
43.5	17.7	8.0	95.5	6.23	6.7	41.4
37.8	16.9	8.5	101.2	6.23	6.7	36.3
36.4	16.6	6.6	97.3	5.55	6.6	39.0
34.4	15.7	5.4	93.5	5.75	6.7	39.8
33.0	12.7	13.3	100.6	6.05	6.2	33.7
32.3	16.5	8.7	96.4	5.87	7.4	38.4
30.8	17.3	8.9	98.9	5.93	6.6	43.7
30.2	16.7	7.5	93.7	5.78	6.0	35.0

The mystery pitcher who throws a pitch from the same height and release with similar traits (but a whole lot harder) is none other than Mason Miller. (The rest of the list is Bryan Abreu, Shawn Armstrong, Jhoan Duran, Cade Smith, Bubba Chandler, and Michael King.)

Now Bowlan is not Miller, the velocity difference does matter, and Miller has better secondary pitches overall than Bowlan has. However, there is something to the pitch characteristics from this release point that is similar in outcome between the two, and that is worth digging in a bit more into.

If we limit our search to 4-seam fastballs thrown with at least 16″ IVB, a release height between 6′ and 6.5′, and an arm angle between 30 and 45 degrees, we find that Miller and Bowlan ranked 1 and 2 in % of total pitches thrown with those characteristics. We find they are 1 and 2 by a large gap on those type of pitches to the rest of the field. They are also 3 and 4 in the average height at the plate. There are also some other pitchers that start to cluster around them in Cam Schlitter, Aaron Civale, Jason Adam, Gavin Williams, and John Curtiss. There appears just doing some column sorting that there is something special about these two fastballs and the ability of these pitchers to locate them in an advantageous place given their traits. In theory, a smart baseball team has a model that would have told them this quickly and would be looking for such an outlier outcome, but most of us in the public don’t have that and need a push, like someone mentioning the specific thread to pull on.

So is Jonathan Bowlan a late inning monster in waiting? Maybe. There is more than just fastball traits that make a pitcher good, but it is certainly a really good place to start. It certainly makes him much more interesting than the random AAAA reliever he was viewed as. If the Phillies can sculpt the rest of the profile even into a 7th/8th inning arm, Bowlan has 6 more years of team control left that they could take advantage of that development.