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<\/a><\/p>\nThese points were brought to Dan Wilson before Saturday\u2019s game. He shot down either premise.<\/p>\n
\u201dThat\u2019s pretty negligible from what we\u2019ve seen before,\u201d Wilson said of the decline in bat speed. \u201cIt\u2019s colder weather- there\u2019s just a lot of different factors that could be involved there. That\u2019s not something that\u2019s concerning us. Obviously, we track, we monitor, but there\u2019s nothing that\u2019s discernible. We\u2019re fourteen games in, there\u2019s so much more season to go. We want to get off to a good start, obviously as a player you want to get off to a good start, but you know, sometimes those things take a little bit of time to get going. It\u2019s not anything different.\u201d<\/p>\n
The first thing to point out is only three Mariners have bat speed drops greater than 1 mph. Randy Arozarena has lost 3.5 mph from last year (the largest change in the majors), Leo Rivas has lost 1.6 mph, and Brendan Donovan has lost 1.3 mph. The next thing to point out is Arozarena and Donovan are the top two hitters on the team so far by wRC+. Bat speed is important, but it isn\u2019t everything.<\/p>\n
Now, there are several players with <1 mph bat speed drops who have indeed struggled. Josh Naylor, for instance, has lost 0.9 mph, and Cal Raleigh and Julio Rodr\u00edguez have each lost about 0.5 mph.<\/p>\n
But the further you dig into the decimals of bat speed, the more difficult it becomes to separate noise from signal, especially in just 16 games. Let\u2019s look at Julio\u2019s rolling bat speed, for example:<\/p>\n
Bat speed goes up and down naturally over the course of a season. That doesn\u2019t always reflect a change in ability. These ebbs and flows can partially be attributed to the measurement itself. Bat speed is captured at the moment when the sweet spot of the bat crosses with the path of the ball. In other words, it tells us how fast the barrel is traveling at point of contact (or missed contact, in the case of whiffs).<\/p>\n This \u201cpoint of contact\u201d piece is crucial. A swing isn\u2019t one, constant speed. It starts slow as the batter fires, and gains speed as the batter follows through. The \u201cbat speed\u201d for any given swing not only depends on how fast the batter swings, but how far they progress in their swing by the time the ball reaches the plate.<\/p>\n What does that mean for interpreting bat speed data? Well, that means observed bat speed can change with the pitch type, velocity, location, and the batter\u2019s ability to identify such variables out of the pitcher\u2019s hand. So if Julio took the exact same swing at a 99-mph fastball on the inner-third as he did on an 84-mph sweeper out of the zone away, he\u2019s not likely to record the same \u201cbat speed\u201d on both swings. And that\u2019s before considering how Julio might change his swing to match each pitch. From that perspective, bat speed is not only a matter of physical strength and ability, but a function of timing and circumstance.<\/p>\n For batters like Arozarena, who display very large changes in bat speed, it\u2019s worth considering the underlying changes pushing their swing to new\u2026 slows:<\/p>\n But for pretty much every other Mariners\u2019 batter exhibiting a decline (or gain) in bat speed, there simply hasn\u2019t been enough time to say what, if anything, is different. I\u2019m more likely to look at slower swings as a symptom of early struggles, rather than a cause. I kind of think the Mariners\u2019 timing is just off.<\/p>\n Now, one theory that\u2019s cropped up to explain the drop in bat speed is Seattle\u2019s cold weather. Several people have pointed out the relationship between bat speed and temperature, noting swings are slower when it\u2019s cold and faster when it\u2019s hot.<\/p>\n I did some math on this<\/a> last week for FanGraphs. My conclusion was, yes, bat speed likely depends on the temperature, and colder means slower. As Patrick Dufor points out in an excellent follow-up analysis<\/a>, some of that could be the drag created by denser air at lower temperatures. But Dufor also notes drag doesn\u2019t quite explain the full change. It\u2019s possible batters might just be less comfortable in the cold. Julio agreed in an interview<\/a> with the Seattle Times. \u201cWe\u2019re not trying to swing slower; it\u2019s just cold as (expletive) in Seattle,\u201d he said, responding to concerns about the team\u2019s bat speed decline.<\/p>\n Regardless, I estimated the change in bat speed at about 0.2 mph per 10 degrees Fahrenheit. That\u2019s not a lot. While Seattle is the coldest city in the majors over the course of the season, it\u2019s typically not the coldest city in the early part of the season. Lots of places are cold right now<\/a>. In fact, T-Mobile Park is more neutral than you\u2019d expect in April. It\u2019s the late summer, when the rest of the country warms up and Seattle still has some bite after sunset, that we see the park flex its muscles<\/a>. That\u2019s to say, yes, it\u2019s possible the Mariners are swinging slower because of the cold. But it\u2019s probably not a big issue, and certainly not one unique to them. And it\u2019s not the only thing that could be pushing bat speed down.<\/p>\n Again, my sense is the Mariners were kind of just bad the first two weeks of the season. I think their timing was off, I think they were swinging at bad pitches, and I think they were falling behind in counts. Each of those things could explain their bat speed slump, and I doubt it\u2019s the other way around.<\/p>\n The Mariners entered the weekend with a 79 wRC+. After walking all over Astros\u2019 pitching the last two nights, they enter Sunday with a 93 wRC+. We are not even 10% of the way through the season. It can swing in a jiff.<\/p>\n","protected":false},"excerpt":{"rendered":"The Mariners are swinging slower and hitting worse, but connecting these dots isn\u2019t as simple as it seems.…\n","protected":false},"author":2,"featured_media":674184,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2392],"tags":[5,620,4,619,65,54376,3235],"class_list":["post-674183","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\/116392456763089268","error":""},"_links":{"self":[{"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/posts\/674183","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=674183"}],"version-history":[{"count":0,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/posts\/674183\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/media\/674184"}],"wp:attachment":[{"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/media?parent=674183"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/categories?post=674183"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rawchili.com\/mlb\/wp-json\/wp\/v2\/tags?post=674183"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/a><\/p>\n<\/a><\/p>\n