Pound the Knees, Steven

The Toronto Blue Jays have recently traded for left-handed pitcher Steven Matz. Matz’s 2020 was a year to forget – join the club Steven – but FanGraphs projects him to slide into the bottom of the Jays starting rotation, and pitch about 132 innings this year. Let’s take a look at who Matz is as a pitcher, and why a change in fastball location is something the Jays coaching staff might consider.

Matz pitched only about 30 innings last year, so in the interest of sample size, I will also be using statistics from 2019 and 2018. Here is what Matz’s last three seasons looked like:

There is a lot of moving parts in there, but I’d like to direct your attention to the fastball ratings. Specifically, how Matz’s fastball, in the past three seasons at least, had an above average velocity, and a below average raw spin rate. That in and off itself doesn’t make a pitch “good” or “bad,” but might hint at its effectiveness in different parts of the zone.

Matz stopped using his four-seamer in 2018, and now only throws one type of fastball – a sinker. The sinker is his bread and butter pitch; he has thrown it over 50% of the time in each of the past three seasons. It sits in the 93-95mph range, with a spin rate that has been increasing, but was still under 2,300 rpm in 2020. And there just might be a way for Matz to get more out of it.

Courtesy MLB Statcast

I’m not sure how familiar you are with Bauer units. Yes, that Bauer, the reigning Cy Young award winner. The formula for Bauer units is really simple; it’s just the spin rate of a pitch in rpm, divided by its velocity. Why would we want to do that? It allows us to compare and classify pitches as high spin, or low spin, while normalizing for velocity. Fastballs thrown at a higher velocity tend to spin at a higher rate, and Bauer units allow us to remove velocity from the equation when comparing how “spinny” a particular pitch is.

Why is that important? According to the linked Driveline article, the average MLB fastball is around 24 Bauer units. Fastballs with higher Bauer units tend to be more effective up in the zone; these are the fastballs that seem as if they are “rising” to the hitter, and hitters struggle to square them up. The poster boy for a higher Bauer unit fastball is – ironically, if you know their UCLA and even pro history – Gerrit Cole. In 2020, Cole averaged 2,505 rpm on his four-seam fastball at 96.7 mph. That’s 2,505/96.7 = 25.90 Bauer units. And here is Cole’s four- seam fastball heat map from 2020, with a clear preference for locating his four-seamer up in the zone.

Courtesy MLB Statcast

This brings us back to Steven Matz. Here is a table of his sinker Bauer units from the past three years.

YearSinker RPMSinker VelocityBauer Units
20182,06993.4 mph22.15
20192,10293.3 mph22.53
20202,23094.5 mph23.60
Courtesy MLB Statcast

The sample size for 2020 is not great, but regardless, Matz’s sinker is a low spin offering and should therefore be more effective low in the zone. Let’s see what the batted ball data says.

The above is only for the sinkers in the three seasons 2018 – 2020. When Matz throws the sinker in the bottom third of the zone, and contact is made, you can hear it. We have exit velocities of 93, 95, and 97mph. However, after you hear the loud contact – with the advances in fielder positioning, shifts etc. – the next thing you hear is probably the smack of the ball landing in an infielder’s glove. That’s because the launch angles in the bottom of the zone are all below 10 degrees, with the lone exception being when Matz misses down to his glove side. Do the outcomes line up with the underlying metrics?

If Matz stays away from the middle of the plate, he has more success down in the zone. The wOBAs are decreasing as we travel down in the zone to Matz’s glove side: .342, .302, .175 from top to bottom – as well as to his arm side: .349, .250, .151. Down to his arm side seems to be his most effective location: wOBAs of .151 in the zone, and .145 on the chase, driven by launch angles of 3 and -6 respectively.

With all that out of the way, let’s take a look where Matz has actually been throwing his sinker in the past three years.

Well, what do you know – Matz has mostly been working his sinker up in the zone. Remember that location with low wOBAs and launch angles from the pictures above? Matz has gone that way hardly at all. The reason, of course, might be that if Matz goes down and to his armside, he catches the batter off-guard and that’s why he’s been successful when he has gone down there when he has. Yet I wonder if this is something the Jays might have picked up on? We’ve all read the stories of Astros targeting high spin guys in trades in their World Series years, and getting them to work up in the zone more. Gerrit Cole is a prime example of that. Could the Jays have seen a potential adjustment to be made and bought low on a pitcher coming off a disastrous 2020?

There is obviously more to a pitcher’s plan of attack than just location of one pitch; how a pitcher’s full arsenal of pitches compliment each other, pitch tunneling, all of those are important. I could be way off base, but now I’m curious whether Matz’s sinker will stay more or less the same in 2021, or if we’ll see him try to keep it lower in the zone a little bit more.

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