Does Jared Jones Have The Best Fastball In Baseball?
He's only thrown 38 of them in the Majors... but maybe?
Most fastballs sacrifice something. Whether it’s in the vertical approach angle (VAA), the induced vertical break (IVB), the velocity, or the extension, there generally needs to be some sort of tradeoff between these factors due to the limitations of the human body. Tall pitchers generally throw harder and extend further off the mound but struggle to release the ball low to the ground, making it difficult to create a tricky vertical approach angle. Smaller pitchers, on the other hand, might not have as much extension or velocity but have an easier time getting low at release, allowing for a flat approach angle that confounds hitters. The necessity of making these tradeoffs is true for everyone besides, apparently, the Pirates rookie Jared Jones, who posits an alternative theory: What if a fastball sacrificed nothing?
At the top, there should be a caveat: the data might be lying to us. The 6-foot-1 Jones averaged 6.8 feet of extension on his four-seam fastball release during spring training. At over 110% of his height, that figure would still rank among the stretchiest pitchers in the game, ranking just behind elite extenders like the Brewers’ Freddy Peralta and the Twins’ Joe Ryan. Last Saturday, in his Major League debut against the Marlins, Statcast had Jones recording 7.6 feet of extension on the fastball release — almost a foot longer than the numbers coming out of spring. So what follows is a somewhat cautious but still relatively confident statement about the Jared Jones fastball: literally no one throws a fastball that matches up.
There’s going to be a lot of numbers in this paragraph, but hang with me. As of April 2, 258 pitchers have thrown at least 10 four-seam fastballs. Only six of them have four seamers that rank at the 70th percentile or above in the big four fastball metrics: induced vertical break (IVB), VAA, velocity, and extension. Four of them are relievers; the other two are Spencer Strider and Jared Jones. Strider is in the 70th or 80th percentile range for all four metrics, consistently well above-average in all categories. Jones’ lowest — lowest! — scoring metric is his 91st percentile IVB.
Ben Clemens covered the gist of this earlier this week in a post for Fangraphs, titled “Let’s All Get Irresponsibly Excited About Jared Jones.” As Ben noted, it’s not just the high-octane velocity that makes the fastball lethal — it’s the velocity, the elite IVB, and the low arm slot combining to produce a fastball that hitters “are swinging under and behind.”
But Ben leaves out what might be Jones’ most distinctive attribute: his (alleged) 7.6 foot extension, which allows Jones to get to that absurd VAA and makes the perceived velocity of the pitch go from 97 mph to something more like 99 mph.
I could proceed to dump so many caveats on this that it might start to sound less impressive — that a 7.6 foot extension for an (ostensibly) 6-foot-1 pitcher might lead to command and injury problems, that the extension measurement might be a mistake, that Jones might be more “geared up” than most veterans because he’s trying to win a spot on the club, that the woeful Marlins managed to square a few of them up — but it’s worth really thinking all of this for a second. Jared Jones, one start into his MLB career, is throwing a fastball that potentially surpasses that of the premier strikeout pitcher in the game.
The reason nobody else lives in the same league as Jones and Strider is that nobody that (relatively) short and therefore low to the ground can also produce huge stride lengths and top-end velocity. (Peralta comes close but sat at “only” 94 mph in his first start this year.) Strider is 6 feet tall and averaged 7.0 feet of extension in 2023. Jones, again, recorded half a foot more than that in his first start.
Let’s assume, for the sake of this post, that the 7.6 foot extension reading is accurate. It would also help to explain his 97th percentile VAA ranking, which is largely influenced by extension but calculated completely independently of it. Also, by the eye test, it looks like he’s getting out extremely far on the mound — there is hardly any dirt between Jones’ plant foot and the grass of the infield.
Speaking of the eye test: the Jones fastball certainly passes it. Look at this pitch!
Good IVB is basically shorthand for “looks like it’s rising upwards,” and it honestly looks like it is. Combine that with how low Jones is able to get at release…
…and the fact that he’s averaging 99 mph of perceived velocity out of the hand, and you’ve got the recipe for a fastball that currently does not exist in Major League Baseball.
(For the record, that is a -.3.7° vertical approach angle, 19 inches of induced vertical break and an average velocity of 97.2 mph. Those stats and his short-form movement plot are below in case you’re interested in the specifics:)
I’m 800 words into this post and I haven’t actually mentioned the slider, which he actually threw more than the fastball in that first start. It’s probably enough to just say it averages 88 mph while dropping nearly two feet under the fastball and move on.
I don’t want to speculate on Jones’ potential as a starting pitcher — he’s started one game in the major leagues. Most likely, he will settle into something less extreme than his undoubtedly adrenaline-fueled debut. But even if Jones is sitting 95 mph instead of 97 mph and extending more like he did in spring training, this is still one of the best fastballs in baseball. And if he can manage to somehow repeat the extension numbers from his first start, it might not be long before the supremacy of Jones’ fastball is widely acknowledged.