One of the most underrated pitchers in baseball
There is a MLB pitcher, whose name I will keep secret until the end of this article, who is quite underrated.
This pitcher made his major league debut in 2015. He was drafted in the 2nd round of the 2009 draft.
In the 2020 season, he struck out 25.4 percent of the batters he faced, which was actually the highest mark of his career. This put mystery pitcher in the 62nd percentile in terms of K%.
He walked 7.0 percent of the batters he faced, corresponding to a 70th percentile BB%.
In addition to mystery pitcher, sixteen other starters (minimum 1.25 PA per team game) ranked in the 60th percentile or higher for K% and the 70th percentile or higher for BB%.
- Zach Eflin
- Hyun Jin Ryu
- Elieser Hernández
- Trevor Bauer
- Tony Gonsolin
- Kenta Maeda
- Framber Valdez
- Zach Plesac
- Nathan Eovaldi
- Kevin Gausman
- Jacob deGrom
- Dylan Bundy
- Yu Darvish
- Clayton Kershaw
- Gerrit Cole
- Brandon Woodruff
Mystery pitcher had a pK-BB% (predictive strikeout percentage minus predictive walk percentage) of 17.0, which placed him in the top thirty percent of pitchers that faced at least 250 batters. His K-BB% was 18.3.
23.2 percent of the batted ball events (excluding bunts) that this pitcher allowed were hit at a 100+ mph exit velocity and 0+ degree launch angle. This ranked 29th highest out of 296 pitchers that faced 90 batters or more in 2020.
5.3 percent of the BBE were of the solid contact variety (borderline barrels). This was the 168th highest.
32.6% were flares or burners. This was the 9th highest.
22.2% were poorly/under batted ball events. This ranked 195th highest.
When hitters put the ball in play against mystery pitcher, hitters had a ton of success, as evidenced by a ridiculous .568 wOBAcon (weighted on-base average on contact).
That .568 number is 57 percent above league average.
As you may or may not already know, pitchers don’t have that much control over what happens when the ball is put into play.
Not even one percent of the variation in 2019 wOBAcon could be explained by 2018 wOBAcon for pitchers that faced 250+ batters both season.
In 2020, only 46 pitchers faced 250 batters or more! BBE data for pitchers is unreliable to begin with. With a shortened season, that unfortunately becomes a bigger problem.
pwOBAcon, predictive weighted on-base average on contact, is a metric of mine. Taking into account four variables (ev100plus_la0plus_percent, solid_contact_percent, flares_burners_percent, and poorly_under_percent), it was built to be predictive of future wOBAcon. All four components are regressed to the mean. The degree to which that is done depends on the number of BBE that pitcher allowed and how strongly the variables correlated year-to-year in my sample data. In the formula, lower percentages are better for all four stats.
Mystery pitcher’s pwOBAcon was .370, roughly league average! His wOBAcon was almost 200 points greater (.568).
No starting pitcher in baseball had a smaller difference (“bigger” negative number) between the two.
Based on his 2020 stats alone, one would predict the mystery pitcher to post a 4.23 ERA in 2021. That would make him a slightly above average pitcher!
In 2020, he had an ugly 9.68 ERA and 7.76 FIP.
His xFIP (4.15) and SIERA (4.05), on the other hand, were decent.
The mystery pitcher is Steven Matz, who was just traded from the Mets to the Blue Jays.
This is a really nice pickup for Toronto, a team that is likely getting an underrated No. 4 starter in Steven Matz, so Hatz off to them.
Can you explain a bit more context on the differentiation between K-BB% and pK-BB%?
K-BB% is calculated by subtracting BB% from K%
pK-BB% is calculated by subtracting pBB% from pK%
Predictive strikeout minus walk percentage is going to be more predictive of future performance than K-BB% is
Message me on Twitter if you have more questions!