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MLB Spin Rates Drop Astronomically in Just 1 Week

Baseball, MLB article at Knup Sports

MLB Spin rates have fallen down to historical lows just one week following MLB’s crackdown on the use of foreign substances. Let’s talk about that!

When Mariners pitcher Hector Santiago was ejected from Sunday’s game versus the Chicago White Sox, he became the first pitcher in the MLB to receive an ejection after the MLB started to crack down on foreign substances used by pitchers.

Santiago claims the substance was a combination of sweat and rosin. Mariners manager Scott Servais said the stickiness was likely due to a reaction between the rosin and sweat due to the heat and humidity during the contest.

After historic numbers and outings from pitchers this season, the MLB has looked to crack down on changing pitchers’ behavior by checking for foreign substances that may help pitchers control and ability.

The MLB is hoping to level the playing field for those in the batter’s box. Before this crackdown, the MLB batting average was the lowest it has been in the history of Major League Baseball.

The Decline in MLB Spin Rates

On June 3, the MLB informed the owners of the crackdown and investigation into pitchers using foreign substances.


Since that day, pitchers have complained, namely Gerrit Cole about either not using substances or for the randomness of the substance checks.

On June 16, the MLB further announced that pitchers would receive a 10 game suspension if found with a foreign substance, and proven by later tests.

Hector Santiago was the first to be ejected, and after a positive test for certain substances, he was handed out the 10-game suspension by the MLB this afternoon.

Since the enforcement of these rules, one thing suddenly became very clear.

Most pitchers were using some sort of foreign substance to enhance their pitching ability. It may not have been to increase spin, but recent spin rates are the most telling factor.

Before the crackdown, spin rates were increasing consistently for the past 5 months. Now with the potential suspension looming and the random substance checks, spin rates have dropped to their lowest since August of 2018.

Many pitchers were also able to reach what was called the “Super Spin” 4 seam fastball, which is classified as 2,500 RPMs or more (RPM = revolutions per minute). Since the checks, the frequency of these types of pitches dropped by 69 percent.

In addition, when looking at the average MLB four-seam fastball, the RPM was sitting at an average of 2,318 rpm, before the institution of this new policy.

Heading into this week’s slate of games, the average four-seamer has dropped to 2,143 rpm.

Drops like this in spin rate have made teams like the Texas Rangers look like offensive juggernauts. They have scored 41 runs in their last 7 games for an average of about 5.85 runs per game.

Their average on the season before that sat below 4 runs per game.

Three pitchers highlight the effect this ban has had on their ability to pitch effectively. Gerrit Cole, Garrett Richards, and Trevor Bauer.

Gerrit Cole, Garret Richards and Trevor Bauer |  A Look at The Numbers

Where to start with Gerrit Cole. It was instantly known that he was upset with the MLB’s new rule, and he made that very clear when he stumbled on interview questions about his potential use of spider tack.

Cole’s four-seam fastball spin rate was 2,164 r.p.m. in 2017, his final season with the Pittsburgh Pirates. Following that season it rose to 2,379 r.p.m. in 2018, his first of two seasons with the Houston Astros, and has been hovering around 2,500 from 2019-now where he is playing for the New York Yankees.

After winning the 2019 ERA title with a 2,530-RPM fastball, the Yankees rewarded Cole handsomely with a massive contract. But after the crackdown, this month his ERA is 4.65 with a 2,358-RPM fastball.

His strikeout rate has also taken a tumble. Sitting at 37 percent before the new rule, it has now dropped 9 percentages to 27 percent in his last 3 starts. A significant decrease.

The drop in spin rate also correlates directly with a rise in ERA’s and batting averages across the league in almost every situation.

Look at Garrett Richards of the Boston Red Sox.

Garrett Richards was one of the many that complained about the crackdown.

Richards stated, “…it has changed pretty much everything for me … I feel like I need to be a different pitcher than I have been the last nine-and-a-half years.”

His average spin rate from 2017 to May of 2021 was 2,604 RPMs, and led to an opponent batting average of .281.

This month, that spin rate has dropped by over 120 RPMs, leading to batters demolition of him at the plate. He has an opponent batting average nearing .385 this month.

Trevor Bauer may be the largest example of the effect that the elimination of sticky substance use has had on pitchers.

The reigning Cy Young winner has found his way to the Los Angeles Dodgers after a phenomenal season with the Reds last year.

The Dodgers gave Bauer $102 million over 3 years after batters hit .172 last year against his fastball that averaged around 2,770 RPMs, a number that has been rising consistently since 2018.

This month batters are hitting .320 against his fastball that has dropped down to 2,582 RPMs.

Let’s take a look at his last few starts. On May 31, Bauer averaged 2824 RPM on his four-seamer, according to statcasts from the MLB.

His next start would drop down to 2608 RPM after the news about MLB investigations into sticky substance use.

Then on June 18, just two days after MLB announced they would be handing out ten-game suspensions, Bauer’s four-seam RPM dropped significantly over 34 pitches. He reached around his averages from 2019, at 2,474 RPM.

Unlike Cole and Richards, this change in spin rates hasn’t completely derailed his game. He is still pitching an ERA of 3.26 in those starts, but two significant stats have changed.

Strike rates and walk rates. His walk rates have increased 3 percent from 7.8 to 10.7, and his strikeout rates have dropped from 32.7 percent before the crackdown to 27.1 percent in his last 3 starts.

Bauer, Cole and Richards aren’t the only ones who have had to make significant changes to their game, it is being seen all across the league. But it is interesting to see these top-notch pitchers (Cole and Bauer) who rely heavily on spin rates are starting to struggle a bit.

The MLB has been needing a movement like this for some time. Pitching has become overpowered and unstoppable in today’s game and a rule like this was becoming necessary.

Whether it was moving the pitchers’ mound back or eliminating sticky substance use from pitchers, I’m glad the MLB is taking action to try to change the game and level out the playing field.

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