MLB details new StatCast technology that measures bat speed. One of my favorite graphics here is the list of fastest and slowest average swing speed, and how both sets are full of good hitters:

Oh, no: Another reason that Statcast doesn’t respect Arraez, right? Not quite. Slower doesn’t always mean worse; sometimes it just means different, in the same way a pitcher with a below-average fastball might still find a way to succeed.

So why does any of this matter? After all, it’s not like very many people would prefer Stanton over Steven Kwan in their lineup, right? It’s sort of like fastball velocity, where you’d obviously prefer to have it than not have it — and in the aggregate, it’s much better to have it — but throwing 98 mph doesn’t automatically make you more productive than someone who throws 92. It’s a tool, not the answer.

Still, the data makes it pretty clear. If you’re not an outlier unicorn in terms of bat control like Kwan or Arraez, you’d probably like to swing hard if you could.

MLB.com

There are hitters who are known for keeping the bat in the zone longer, and they tend up to contact hitters. They start their hips to get their body moving, but they commit their hands very late. This allows them time to correct their swing if they misjudged the pitch. I’ve heard Tony Gwynn and Derek Jeter described this way, but I suspect hitters like Ty Cobb, Joe DiMaggio, Pete Rose, Rod Carew, and Wade Boggs fit the mold as as well.

If you look at this graph at Baseball Savant, what you see is that while Arraez’s swing is slow, he squares up the ball better than anyone. The graph also makes clear why Juan Soto is go good, as he combines bat speed with the ability to square up the ball.

It will be nice to see what that graph looks like when we have a couple of thousand of swings for each batter.