Stuff+ is statement on the physical properties of a pitch, where 100 is average and higher is better. It takes a bunch of data points\u2014velocity, spin, movement, etc.\u2014and estimates the effect of those characteristics on performance. In broad strokes, it works very well, and there\u2019s a reason both public-facing analysts and teams invest in these models. Andr\u00e9s Mu\u00f1oz is the Mariners all-time leader in Stuff+<\/a>, if that helps paint the picture.<\/p>\n Anderson\u2019s fastball so far grades at 91 by tjStuff+, Nestico\u2019s version of the model. (I\u2019m not picking on Nestico here. His just happens to be one of the few models available for Spring, and again, I really enjoy playing around in his website.) For reference, that\u2019s about 10% below league average and would be one of the lesser four-seam grades in MLB. He\u2019s only thrown 28 fastballs\u2014another element of this discourse to keep in mind\u2014but we can see why the models are unimpressed: it\u2019s not very fast. His average four-seamer of 93.4 mph would be below average by MLB standards, and you don\u2019t need fancy statistics to tell you more velocity is good.<\/p>\n The \u201cshape\u201d (or vertical and horizontal movement) of the pitch is also not unique. Great fastballs come in all shapes and sizes<\/a>, and nothing about Anderson\u2019s movement profile prevents it from being a highly effective pitch. But his fastball doesn\u2019t exhibit the traditional top-rail four-seamer rise to coax whiffs at the letters, nor the bowling ball quasi-sinker that can plop down in the zone. From the perspective of these models, it\u2019s just kind of\u2026 generic.<\/p>\n Again, none of this is disqualifying. Plenty of great pitchers have a lesser, nondescript fastball\u2014some pitchers don\u2019t even throw a fastball. But the concern here is Anderson was billed as having a remarkable fastball. FanGraphs, for instance, gave it a 70 grade on the traditional scouting scale. That\u2019s hard to square with what we\u2019re seeing in these models, even in small samples. If the fastball has indeed been overstated, it\u2019s possible there\u2019s some limit to his projection.<\/p>\n But as Nestico or anyone else developing these models will tell you: stuff isn\u2019t everything. It doesn\u2019t capture location, tunneling, and other matters of deception. As Brendan Gawloski noted in his report for FanGraphs<\/a>, that\u2019s a big part of what makes Anderson\u2019s fastball an elite pitch:<\/p>\n His fastball sits 92-95 mph with vertical ride, and it plays up because his loose arm action hides it until the very last moment. It generated a whopping 35% miss rate in 2025. The way his fastball plays means Anderson\u2019s command of it doesn\u2019t have to be precise; it rides enough to evade barrels in the strike zone.<\/p>\n Jerry Dipoto offered a similar account when Kate Preusser asked him about it on Sunday. Anderson\u2019s delivery naturally hides the ball from the batter until the last moment, Dipoto said. He throws from an unusually high arm slot for a lefty, while still getting solid extension down the mound. It\u2019s just not a \u201clook\u201d batters see very often. Public models can\u2019t capture that, Dipoto said.<\/p>\n And it\u2019s not just Dipoto saying it. Mariners\u2019 hitters have reported issues picking up the pitch in practice.<\/p>\n \u201cIt\u2019s got some teeth on it,\u201d Ryan Bliss said. \u201cIt\u2019s spinny, it\u2019s sneaky. It\u2019s 93-94, but it feels like it\u2019s 96-97. And he will throw it any time, he\u2019ll throw any of his pitches any time for strikes, so you don\u2019t know what\u2019s coming. It\u2019s an uncomfortable at-bat.\u201d<\/p>\n And look, I\u2019m not going to tell you that I, sitting here in my office, in my sweats, mustard still staining my fingers from lunch, can \u201csee\u201d even the weakest professional fastball. But yeah, I get how this pitch might appear out of nowhere from the perspective of a batter.<\/p>\n The other thing stuff models don\u2019t capture? Arsenals. In addition to the fastball, Anderson throws a slider, changeup and curveball. Each of these pitches grades a more favorably by stuff models, and each gets the same boost from his deceptive arm action. This is one thing we (and by we I mean people much smarter than me<\/a>) are starting to model publicly, and it does appear to be a big factor in whether a pitch or pitcher is effective. When Anderson releases the ball, batters might expect the incoming pitch to move at four different speeds and in four different directions. They can\u2019t cheat and sit on any one offering, and because of his hocus-pocus delivery, they can\u2019t afford not to cheat. It\u2019s a blender of deception that helps his velocity play up.<\/p>\n \u2026. in theory. We have yet to see the sum of this deception in games that count. We have data telling us one thing, and we have the Mariners telling us another. That\u2019s why there\u2019s dissonance. But while I normally wouldn\u2019t put stock in typical Spring Training chatter from the team, I certainly value action. And the Mariners, somewhat literally, put $8.8 million where their mouth is when they drafted him. That\u2019s worth something, as Justin Hollander pointed out Monday.<\/p>\n \u201dIf the Seattle Mariners draft him third overall in the country, you can bet our models like him,\u201d Hollander said.<\/p>\n That\u2019s the strongest point in favor of Anderson\u2019s fastball, in my opinion. To be clear, Kumar Rocker, Max Meyer, and Ian Anderson were also drafted third overall within the last decade, so it\u2019s not quite ipso facto in the way Hollander asserts. But the Mariners are indeed a top five collection of pitching thinkers across the league, and (I\u2019d argue) the best organization at knowing who to draft. They\u2019re aware of the models, and they invested anyways.<\/p>\n This level of scrutiny isn\u2019t entirely fair to Anderson. He is still a prospect after all and has yet to make a professional appearance outside these exhibitions. His stuff is not defined by 64 pitches in any setting, and a few outings while ramping up for the season aren\u2019t representative of his current abilities. Regardless, he\u2019s sure to get better with experience, whether we can measure it or not.<\/p>\n Still, the scrutiny isn\u2019t quite misplaced. The hype heaped on Anderson<\/a> has been pushed to rare levels<\/a>, and the emphasis of the narrative is how fast he\u2019s expected to move<\/a> through the minors. The Mariners are trying to win a World Series this year, and there are legitimate questions about the depth of their rotation. It\u2019s fair to wonder whether the team is serious about accelerating him, and whether he is ready for the jump. Is he now the sixth starter? Seventh? Eighth? I\u2019m not sure. But my sense is Anderson, much like his fastball, will sneak up on us quick.<\/p>\n","protected":false},"excerpt":{"rendered":"Kade Anderson\u2019s fastball is neither fast nor shapely, but that doesn\u2019t mean it isn\u2019t good. Anderson\u2019s first two…\n","protected":false},"author":2,"featured_media":615999,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2392],"tags":[5,620,4,619,65,54376,3235],"class_list":["post-615998","post","type-post","status-publish","format-standard","has-post-thumbnail","category-seattle-mariners","tag-baseball","tag-mariners","tag-mlb","tag-seattle","tag-seattle-mariners","tag-seattle-mariners-analysis","tag-seattlemariners"],"share_on_mastodon":{"url":"https:\/\/channels.im\/@mlb\/116202517140683099","error":""},"_links":{"self":[{"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/posts\/615998","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/comments?post=615998"}],"version-history":[{"count":0,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/posts\/615998\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/media\/615999"}],"wp:attachment":[{"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/media?parent=615998"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/categories?post=615998"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/tags?post=615998"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/www.rawchili.com\/mlb\/wp-content\/uploads\/2026\/03\/bafkreidckdeas6r3mr7ajmmp6el66tlgmtbzbs5klr6d2s2pw7iod6ahcy.webp.jpeg\"\/)
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