Departing the Fly Ball Revolution — Apr 20, 2021, A Review

Yesterday, I reviewed the hitters who had raised their FB% marks by at least 10% through Apr 17 versus 2020. Let’s now switch gears to reviewing those hitters who saw their FB% marks decline by at least 10% through Apr 18. Did these early FB% declines suggest a down power year? Let’s find out.

Once again, I somewhat arbitrarily highlighted the Diff column in red if the hitter’s FB% remained down enough versus 2020 over the rest of the season to declare the early FB% decline was meaningful. Only five of the 18 hitters “earned” a highlight, reminding us that regression to the player’s mean is a powerful force.

Seventeen of the 18 batters saw their FB% marks increase off their down marks through Apr 18. That’s crazy! A whopping 14 of them experienced double digit increases. Six of them actually posted a higher FB% over the rest of the season than they did in 2020! So while it doesn’t mean we should completely ignore batted ball type distribution rates early on, we shouldn’t make moves based on such data. Sometimes it means something, but knowing which hitters it does ahead of time is an impossible task.

Let’s discuss the five hitters who were highlighted in red.

Shockingly, Bryce Harper’s FB% was under 30% through Apr 18, which is not something you want to see from a guy who owns a career 21.1% HR/FB rate. He did boost that FB% back up over the remainder of the season, but that level was still well short of his 2020. However, his 2020 mark was actually a career high and only the second time his FB% exceeded 40%. His rest of season FB% was actually just a touch higher than his career average, so it’s clear that the early FB% decline was a complete fluke and reversed quickly. It’s a good thing, as he just posted the second highest HR/FB rate of his career and needed all those flies to fully take advantage.

We’re used to Eric Hosmer not hitting enough fly balls, but that all changed in 2020, when he posted a career best mark and just the third time it sat above 30%. While he’s done that twice before and immediately posted a sub-30% mark the following year, perhaps this was finally the time he would hold onto his gains? Nope, it wasn’t to be. While he was better over the remainder of the year, he was still essentially matching his career average, which is simply too low given his over-the-fence power. It didn’t help that his HR/FB rate plummeted to its lowest mark since 2014 either.

Like many others discussed on these lists, Marwin Gonzalez was coming off a career high FB% in 2020, so it looked like a bigger drop than it was if instead comparing to his career average. Over the rest of the season though, he still posted his lowest mark since 2014 and then combined the lack of flies with his lowest HR/FB rate since 2013.

Owning mammoth power, we want Aaron Judge to be hitting a good rate of fly balls, though perhaps not too high of a rate that would hurt his high BABIP potential. So when he opened the year with a sub-30% mark, it was perplexing. What the heck is Judge doing hitting so few fly balls?! He certainly picked it up over the rest of the season, but it still was well below his 2020 mark. That said, his FB% has jumped around from the low 30% range o the low 40% range, so it’s anyone’s guess what you’ll get from him in a given year. Obviously it’s an important metric given that his main fantasy contribution is his home run power.

Mike Trout only played for about another month before getting injured and missing the remainder of the year. His early FB% was already down, but he was the only one on the list to post an even lower mark the rest of the way. He was having another elite season, though unsustainable given the .456 BABIP, before going down, so I’m curious to see how much this lost time affects his draft day cost. I’m also concerned that the severe calf injury could hamper his running game.