The underrated part of Scott Alexander’s sinker

Much has been made of the Royals new and fun tool in the bullpen. Scott Alexander hasn’t been a revelation this year, but he’s instead been a solid reliever who can pitch multiple innings and also work out of a jam. Coming into the year he also wasn’t thought to be a large part of the Royals bullpen and late game strategy, so his emergence as a good left-handed reliever is a nice turn for a lost season overall.

He’s not without his flaws. He doesn’t strikeout enough batters to be a truly great reliever and his command can get a bit loose at times, but the part of his game that he centers his whole approach on (getting groundballs), he does just as good as anyone else. If Aroldis Chapman and Kenley Jansen focus on strikeouts, Dan Otero focuses on not walking batters, and Peter Moylan just wants to get right handers to swing at his slider, then Alexander wants batters to hit the ball into the ground. Batters have done just that this year:

Since 2010, only two pitchers have had a groundball rate higher than Alexander. One of them is Zach Britton, who Alexander gets compared to often because of his sinker. The other is Brad Ziegler, who we can rule out because he throws the ball like this:

The comparables to Britton stop really at the groundball%:

The thing that makes Zach Britton into Zach Britton was both the obscene groundball rate and the strikeout and home run rate. Alexander can’t quite pace him there, and you can see the large difference in the peripherals. Britton strikes out more batters, walks fewer, gives up half the home runs, and easily beats Alexander in both ERA- and FIP-.

But here is where Alexander has Britton beat at the game that Britton is known as being the best for.

Of pitchers who have thrown at least 500 sinkers since 2007, Alexander has generated more whiffs on the pitch than Britton, and the 3rd most in all of baseball. Yes, at the top of that leaderboard is a mid-40’s Randy Johnson, but after him are arguably the three best sinkers we’ve seen the past few years.

A moment of silence for Jonny Venters. He was almost as good as Britton when he was at his peak, but since 2012 Venters has had Tommy John surgery three times and four times in his life.

And when it’s come to getting grounders and avoiding fly balls/line drives on the sinker, Alexander has been a bit better too in his career. Just looking at this year alone, Alexander sits alone atop the sinker leaderboard in whiff%:

An interesting thing about Alexander’s slider is that it isn’t at the top for most vertical or horizontal movement, but instead just does a good deal of both.

Sinkers usually get their love for dropping like a bowling ball, but Alexander’s also runs into right handed batters. This year it’s moved more horizontally than in the past, and he’s also throwing it a few miles per hour faster.

There is both more horizontal movement and more sink to the pitch than in years past (the furthest left dot being 2017). Now it’s a potential weapon against both left and right handers, giving him the ability to get whiffs with it.

The sink is of course nice, but it’s the additional horizontal movement that helps get swings and misses. Last year batters hit .309 on his sinker. This year they are hitting .256 on it. Last year 6.17% of his pitches were swinging strike sinkers. This year it’s been almost 10%.

9.8% of the total pitches Alexander has thrown this year have been sinkers that batters chased and missed at. Comparing it to other notable pitches:

Nothing will ever beat how well Andrew Miller throws his slider, but at least we’ll still get to see Scott Alexander throw his sinker.