Pitcher Evaluations: Post Sticky Stuff Ban Memo | RotoGraphs Fantasy Baseball – fangraphs.com

Note: During the All-Star break, at least Paul and I are going to break down pitcher results and they will all be in this article for easy reference. The article will grow throughout the week as more and reports get done. Please submit pitcher recommendations in the comments making sure it’s only actionable pitchers (no Cole’s or Giolito’s).

Background

For those coming back from a two-year submarine tour, here is some background on the current state of the sticky substance ban. Pitchers who use sticky stuff on baseballs create more spin and more spin can lead to more strikeouts for certain pitches. Someone(s) felt it was finally important to start enforcing the rule after decades of turning a blind eye. Here is the time timeline for the crackdown.

• April 1: Balls were collected that were deemed to have sticky stuff on them.
• May 15: The spin rate across the league dropped. It almost seemed like teams got a double-secret memo before the official memo.

The sticky stuff crackdown has produced just an absolutely bonkers reduction in spin rates across the league. We really don’t have a good historical parallel for how low RPM will end up, but this change is going to cut K% and boost runs by a lot. https://t.co/c5ST8JF3t0 pic.twitter.com/k98ASf223q

— Rob Arthur (@No_Little_Plans) June 25, 2021

• June 15: Official MLB memo came out that stated that umpires were going to start cracking down (leaked on the 14th).
• June 21: Umpires started checking pitchers.

So there was basically a month and a half when pitchers were applying whatever they wanted. A month when everyone knew a crackdown was coming. And this last month of being checked every inning.

Once the crackdown was going to happen, several people wrote about the potential effects. The Athletic noted the pitches that would see the largest effect from having less spin would be four-seam fastballs and sliders.

Also, we’re focusing only on four-seamers and sliders because, as you can see from this image, the effect of spin on the strikeout rate for at-bats ending with a four-seam and slider are severely affected by how much spin is on the ball.

The relationship isn’t particularly strong in terms of predictiveness — there’s a lot more to the effectiveness of a pitch than just the spin rate — but there is a relationship here that matters.

The same article stated that the average drop in strikeout rate would be 1% point. In a separate Athletic article, Eno Sarris went into a few reasons why pitchers might not be struggling as much as originally predicted.

For one, you see in Codify’s tweet above that velocity has been up a little as spin is down. It could be that pitchers are compensating for the lack of spin by throwing harder, it could be that weather is just leading to faster fastballs, it could be that without some gooey substance pulling back on the ball, more energy is put directly into the fastball, or it could be some combination of some of these factors. Either way, faster fastballs perform better — the slugging percentage this year on a fastball between 92 and 93 is .500, and it drops to .445 on balls thrown between 94 and 95 — so this might be undoing some of the effect of removing spin.

There’s also some evidence that at least some pitchers are going away from the four-seamer and throwing more two-seamers recently, which brings up the specter of in-game type adjustments. Perhaps some pitchers are varying their fastball location more, or their pitch mix, or their velocities — a lot of these things won’t come up in a league-wide assessment, but they could introduce noise to league results.

Simply, MLB has been trying to crack down since the beginning of the season, spin is down, but on an aggregate level, results have not changed.

Pitchers

Dylan Cease

While Cease has not performed the best since the crackdown, the only obvious difference from before and after is his home run rate.

His strikeout and walk are effectively unchanged and his xFIP is down because of more ground balls.

One little small change is the increase in curveball usage. The increased usage has been able to mask that his fastball and slider have performed worse as their spin rates tanked.

It was almost as if the White Sox management and Cease had a pre-enforcement plan to keep his production going. The change might not have been noticeable if he hadn’t had some home run regression. -Jeff

Alex Cobb

Right when the ban seemed inevitable (coincidence?), Cobb went on the IL with a finger blister. Here is his performance divided up by pre-injury, post-injury to the enforcement, and post-enforcement.

He came back post-blister throwing his splitter fewer times, and his strikeout rate is strikeout rate suffered. Since being healthy, he has a 3.63 ERA and it has even matched his sub-3.00 ERA over the last few starts

As stated in the background section, sinkers and splitter results won’t be affected as much by a lack of sticky stuff even though it looks like Cobb was using some by the drop in spin rates.

Simply, it seems like Cobb finally got healthy and the results have improved. -Jeff

Shane McClanahan

There is a lot going on with McClanahan so it’s tough to separate any changes from a lack of sticky stuff. He struggled in June with a 5.01 ERA (3.26 xFIP) and that might be from facing a lineup more times. From being called up to his June 9th start, he averaged facing 17.5 batters per game. Since then, it has been 22 batters. He’s definitely been better the first time through the batting order (1st TTO: 3.33 ERA, 2nd: 4.97, 3rd: 3.53)

Also, he’s doubled the usage on his above-average curve (18% SwStr%) from 8% to 16%. Finally, his fastball spin rate is down an average ~60 PM along with his average fastball velocity down 0.6 mph. During the double decline, his swinging-strike rate on the pitch is down from 9.4% to 4.8%. How much is from the velocity and how much from the spin? Or because a hitter is seeing it for a second or third time?

He’s changing but it’s nearly impossible to quantify the exact effects of the enforcement of the rule. -Jeff

Brady Singer

As a sinkerballer (50% GB%), none of Singer’s pitches have seen a spin rate drop and all of his June struggles can be linked back to a start when he walked five Yankees. -Jeff

Tarik Skubal

Skubal is having an interesting season and possible changes in sticky stuff have nothing to do with it. The changes revolve around adjustments in his pitch mix. In May he dropped his splitter (10% SwStr%) and went back to his change (17% SwStr%). Then in June, he started throwing a sinker (8% SwStr%, 50% GB%). Here are his pitch usages and results during each period.

With the addition of the sinker, he trading off strikeouts for groundballs.

Looking into his pitches, there are definite breaks when his spin dropped. They were not on the same day which seems to jive with his constant tinkering this season.

While he’s lost some spin, the two pitches are performing the same or better. While Skubal’s spin has dropped, his pitch mix changes explain his up and down season. -Jeff