Gunnar Henderson: Destroyer of Four-Seam Fastballs

Baltimore Orioles phenom Gunnar Henderson tore through the two highest levels of the O’s minor league system as a baby-faced 21 year old that was, on average, three to five years younger than his competitors. Henderson then capped off a meteoric ascension to the top of prospect lists with a month long stint in the majors that did nothing but fuel the hype machine created around him, justify the heaps of praise he was receiving, and cement himself as one of baseball’s brightest young future stars.

Henderson exhibited all the tools one would use to craft an ideal baseball player. Defense? He can play shortstop or third base at a high level. Throwing arm? Henderson has that too, with his average throwing speed within the top 26% of all qualified fielders. Overall speed? The boy is fast, swiping 23 bases between AA/AAA/MLB. Batting eye? Of course, and it’s a skill Henderson has improved at an exponential rate since he turned professional – he managed to trim his strikeout rate by about five percent from 2021 to 2022 and posted a 12.1% walk rate during his short stint with the Orioles.

You really didn’t think I’d forget his hit tool, did you? Now you’re just being a silly goose. Henderson raked at every level of the minor leagues, against all levels of pitching, against all different kinds of pitches. When you look specifically at his time with the Orioles in September and the StatCast data that accompanies it, one thing about Gunnar Henderson becomes abundantly clear: he absolutely pummels fastballs.

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Run Value is a cumulative, running count statistic that measures a player’s contribution to (or deduction from) their team’s run expectancy, which is based upon the 24 out/baserunner scenarios that could occur in any given inning. In just 132 plate appearances, Gunnar Henderson accumulated a Run Value of 6 against four-seam fastballs. That is the second highest total of every single Baltimore Orioles hitter, higher than guys who spent the entire season at the MLB level. His average exit velocity was just over 96 MPH meaning on average, Henderson was producing a ball classified as hard hit (95+ MPH exit velo) every time he made contact with one. All of that quality contact added up to a 61.5% hard hit rate, which ranked third among Orioles hitters (behind Ryan Mountcastle and Jonathan Arauz) and 38th among all MLB hitters. For a hitter of his age, that is incredible!

In his time as an Oriole, Henderson hit an astounding .371 against fastballs with a Ruthian .686 slugging percentage than included three home runs. That slugging percentage against four-seamers was higher than that of Juan Soto, Bryce Harper, and Vladimir Guerrero Jr. The small sample size is an obvious caveat that must be taken into account, but playing with numbers is fun!

Gunnar Henderson: Destroyer of Four-Seam Fastballs

Henderson doesn’t discriminate when it comes to four-seamers. Premium velocity? He’ll just take a 97 MPH fastball, go the other way, and send it over the left center field wall. Something in the low 90’s? No worries, Henderson will get to those too.

High, low, or middle, Gunnar Henderson is going to square it up if it’s in the zone. (Source: Baseball Savant)

The impact Henderson was able to make against four-seam fastballs in such a short period of time is nothing less than remarkable. A full major league season with pitchers adjusting to Henderson’s approach will almost assuredly lower his stats against heaters. Don’t worry though, Gunnar Henderson has adjusted and improved throughout his professional career and will use his ability to crush fastballs as a pillar to the expansive home he’s building in the Land of Superstardom.