Tigers pitchers are showing revamped sliders in the early 2018 season

There are two types of pitching coach. Some, like Ray Searage or Dan Warthen, acquire a distinctive reputation for their approach, or a particular pitch like the Warthen slider. Others seem a little more utilitarian, taking ideas from everywhere and focusing on each pitcher’s individual approach. Some are gregarious, and happy to expound on their theories. Others offer scant public comment and stay in the background, making their impact a little more difficult to pin down.

Former Detroit Tigers pitching coach Rich Dubee was of the second group. During his two seasons in Deroit, Dubee didn’t give a lot of pithy quotes. He largely stayed in the background. He didn’t promote a particular school of thought or make any bold pronouncements. But that doesn’t mean he didn’t leave a mark, even if his actual style with his pitchers was mostly hands off.

Dubee, who worked with Roy Halladay and Cliff Lee in their primes, was known for his affection for the cutter. While Justin Verlander has vociferously denied throwing a cutter, we first noted in May 2016 that his slider changed dramatically in character that year. Formerly a mid-80s offering with inconsistent command by his standards, Verlander’s new slider was 89-91 mph with more cutting action than depth. And it worked. Verlander got on a roll in early May, and, apart from two outings against the Indians, was nearly unhittable the rest of the year. That hard slider was a big part of the reason why. Verlander had tinkered with a hard slider previously. It didn’t fall out of the clear blue sky when Dubee arrived. Still, it’s pretty hard to see the two as unrelated.

Michael Fulmer already had a hard slider. So did Shane Greene, despite it sometimes being classified as a cutter (it’s essentially the same pitch). Later in 2016, Daniel Norris adopted a much firmer slider as well, and it powered him to a fine second half. How much of it was Dubee’s doing is debatable, but the Tiger slider was a thing. Apart from lowering Matt Boyd’s arm slot, no other element of the Tigers’ pitching staff was so identified with Dubee as that cutter-like slider.

One week into the season, that Tiger slider has largely vanished.

Unlike Dubee, Chris Bosio isn’t the type of pitching coach to lay low. In fact, he has been quite vocal about the strategy and attitude he expects from his pitchers. He has laid hands on seemingly everyone to make slight mechanical adjustments already. He has instituted rapid fire drills to encourage working quickly and to sharpen command. But if there’s one thing (other than pace) that stands out from Tigers pitchers in the early going, it’s the way they are throwing sliders. Something pretty interesting is going on.

Every pitcher listed above is getting more depth on their sliders. And the changes are pretty substantial. We’re only talking about a small amount of games, but changes in things like movement and spin rate stabilize fairly quickly, unlike overall performance. Considering that each has shown good command of the pitch, they seem to be shaping the sliders differently on purpose.

Apart from Farmer, each is throwing their slider slower than they did in 2017. The version thrown by Farmer has always been within the curveball velocity band, however. He’s a bit of an outlier in this grouping.

For the others, diminished velocity has led to improved depth.

It’s trickier to assess the impact of spin rate with sliders than with fastballs or curves. But it is interesting that there are some notable changes which might speak to grip changes or better mechanics. Norris’ slider has showed less spin, while Jimenez’s has showed more. Michael Fulmer’s spin rate is unchanged. Farmer has had a little less spin, but wow, Buck Farmer gets a lot of spin on his slider. In more ways than one, it resembles a curveball more than a slider.

Of course, the fact that a bunch of Tigers pitchers are getting more downward break on their sliders doesn’t necessarily mean anything. It’s not magic. Executing pitches with command is still the key. But the greater depth on these sliders should play to Bosio’s aggressive, north-south approach to pitching. He’s all about manipulating the timing and sight lines of hitters. The ability to go up with the fastball and down with a breaking ball from the same release point has been a key point of emphasis early on. In theory, instead of weak contact, you should generate more whiffs as long as you can continue to throw the slider aggressively at a lower velocity.

It’s interesting that Bosio has made such a dramatic impact already. You don’t always see a new pitching coach come in and institute major changes in his pitchers’ actual stuff after just two months together. Even just promoting an overall philosophy takes time to institute. So far, Bosio has gotten exceptional buy-in from his staff. Whether they succeed or fail this season, his overall impact on them will be a key storyline to watch.