NEW YORK — Indians hurler Trevor Bauer made waves last week when he suggested the use of foreign substances by pitchers was a rampant issue in baseball.

Bauer, who has always taken a scientific approach to his career, said the implication was based on experiments he had performed to see what substances like pine tar could do to a pitcher’s spin rate.

Speaking with Sporting News, Bauer discussed his research and why foreign substances and spin rates are such a big deal.

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(Editor's note: The conversation has been edited for clarity and length.)

SPORTING NEWS: I wanted to give you a chance to clarify that message you were trying to get across with your tweet, because it wasn’t just about the Astros, correct?

TREVOR BAUER: I never mentioned a player’s name. I never mentioned an organization. It’s not about any one person or any one player or organization, coaching staff — nothing like that. It has nothing to do with any specific team or person.

SN: How rampant is the use of foreign substances in baseball right now?

TB: I think everyone agrees it’s pretty widespread. It’s a fairly well-known secret, if you even want to call it a secret. But the issue is we didn’t have the technology before to quantify exactly how big of an impact that can have on a game, on the pitcher’s success, on his overall repertoire, on his future monetary compensation, on whatever. Now we do. We’ve done the research, we know how much it can increase your spin rate, we know how increased spin rate can improve a player. We have free agents getting signed based on having a higher spin rate than another guy. If I can put pine tar on my hand and increase my spin rate 200 RPM and then get a job over another guy who isn’t breaking the rules, how is that fair?

It’s the same argument that was used with steroids: everyone's doing it, there's more home runs and more excitement, it’s good for the game and we’ll just look the other way. What about the guys that don’t want to put that in their body, who don't want to do that? They have to to compete on a fair playing field. Now, this isn't the same where you’re negatively affecting your health. It's just a matter of having pine tar on your glove and making your fingers a little sticky, right? But it still creates an unfair playing field. But now we have the data to quantify how much of an unfair playing field it creates.

SN: You've done your own research experimenting the impact foreign substances can have on a baseball. What exactly have you done to test this and what has it shown you?

TB: So, I sat down with a chemical engineer two years ago to discuss exactly how the surface of a ball would interact with skin and how to create more friction. I mixed non-Newtonian fluids, I've tested slippery stuff, I've tested sticky stuff, all sorts of pine tar sticks, firm grip . . .

SN: Coca-Cola, right?

TB: Yeah, pine tar mixed with firm grip and Coca-Cola. I've tested all sorts of different stuff. I molded my dad’s fingers and 3D-printed molds so that it would enforce the flexion of his fingers. I’ve tested keeping your fingers straight by taping emery boards to the back of your fingers so they don’t flex. I’ve tested all this different stuff to figure out what can affect a fastball’s spin rate. I’ve been after finding a solution to increasing your fastball spin rate for five years.

If you want to high-grade your repertoire, if you want to have an elite fastball, that’s what you have to do. I’ve been after it for five years. Not a single thing that I’ve tested in five years — not just me, people at Driveline, my dad, other research facilities around the country that I talk to — not a single thing. Not one thing have we found that increases fastball spin rate besides a sticky substance.

MORE: Trevor Bauer causes tweet storm

SN: As far as RPMs go, has your research shown you exactly what the difference is?

TB: That depends on the individual slightly and the velocity range you’re throwing at. We tested 10 individuals at 70-ish miles per hour. Some of them averaged 68, some of them were 71, but the goal was to throw around 70. In those tests, it affected spin rate between 250 and 400 RPMs. At higher velocities, around 90, which are more game-like velocities, it affects spin rate between 200 and 300 RPM on four-seam fastballs. It’s very slightly on curveballs and sliders because the mechanism of which the ball comes off your hand is slightly different, but I’ve found ways to affect spin rate on those pitches naturally. Just active perceived rate of pronation and grip tension on the ball and extension, stuff like that.

SN: In response to your tweet, (Astros manager) A.J. Hinch said maybe (Houston right-hander) Gerrit Cole (a college teammate of Bauer's) is getting behind on his fastball more, he’s changing different grips. Are there things a pitcher can do naturally to achieve increased spin rate? Even then, is it going to be as significant as it is with pine tar?

Houston #Astros manager AJ Hinch weighs in on the @LMcCullers43 @BauerOutage Twitter kerfuffle:



"I don't know if it's gamesmanship, or college pranks, or what would make someone have any sort of statement without any evidence, so it's kind of ridiculous that it's even a topic." pic.twitter.com/s1XhjAvX5V — MLB Network Radio on SiriusXM (@MLBNetworkRadio) May 1, 2018

TB: I wasn’t talking about one person or one team. All I can do is quote my research, and my research over the past five years has shown that there’s not a single thing that you do naturally to increase fastball spin rate. That being said, it’s not impossible that exists. It might exist somewhere. All I’m saying is I’ve been after this for five years and I haven’t found anything. No one I work with has found anything that increases it naturally.

SN: As far as sticky substances go, have you shared your research with Major League Baseball, the league office, the players union?

TB: No, because for a long time I wanted it to be proprietary. Why would I take the golden egg and give it away to everybody for free? Now I’ve gotten to a point where I understand it well enough and I’m fairly certain there’s not much way to affect it naturally. Instead of trying to keep it proprietary, to use it for myself since I’m not willing to go out and cheat, I’ve decided to raise the issue and see if there’s something that can be done either to legalize or — if I want to compete on a fair playing field, I have to go out there and use some sort of sticky substance.

That puts my team at risk because if I get caught, I get ejected, I miss games, it affects the bullpen, it affects people’s jobs in the bullpen, it affects the starting staff, it affects every position player who’s trying to win games, trying to win a World Series. But guys are competing on a playing field where guys are doing that night in and night out other places. They choose to take the risk and I’m not willing to do that.

SN: So, what does Major League Baseball do about it as far as leveling the playing field?

TB: That’s got to be their decision. Whether it’s an issue they care to address or not, I mean, it’s been going on in baseball forever. Everybody knows it happens. Managers know, front offices know, players know and no one says anything about it because it’s just kind of accepted. You either have to enforce the rule or you have to legalize it and there’s no good way to enforce the rule. You can’t check a pitcher between every pitch, in between every inning. You don’t know where he might hide something. There’s just no good way to do that. The only way to level the playing field is to allow everyone to use it. That way, if you want to use it you can. If you don’t, you don’t have to.

What will happen is everybody’s spin rates will adjust to be with sticky stuff and then hitters will adjust to hit those spin rates and it will level the playing field for everybody. Spin rate itself doesn’t make a pitch harder to hit. It just makes it further from what the hitters are used to seeing. It takes a pitch further away from average. So, if everybody’s using it, there will be a new average, everyone will fall in their slot relative to what their average is and then it will be fair for hitters and fair for pitchers and it will be a non-issue.

SN: Explain to the casual fan, when it’s not everyone using the sticky stuff, what does more spin do? How is that advantageous, like you compared it to performance-enhancing drugs?

TB: Assuming you maintain the same spin axis — take a given spin axis, whatever it is. Just a dead four-seam backspin. For every 100 RPMs you go up, the ball moves more. That’s the mechanism for which the ball moves. The ball spins, it creates forces in the air which creates movement. So, if I can increase it 100 RPM or 200 RPM or 400 RPM, then the ball moves more, it moves differently. But it appears out of the hand the same. The ball just ends up 2 inches different or 4 inches different or whatever than what the hitter expects. The hitter can’t track the ball the last 15 to 20 feet of flight because it’s moving too fast. Hitters are swinging based on the information they get in the first half of flight. If they see one thing and swing to a certain spot, and then the ball ends up three or four inches different than what they expect, it creates massive amounts of swing and miss. That’s why, when you look at spin rates — all the numbers, if you sort any pitch by spin rate and swing and miss rate and hard contact and batting average against and everything — as the spin rate goes up, those all fall.

If I can average 2,600 RPM on my fastball instead of 2,250, 2,250 lands me right in the middle, dead-average. When I’m sitting 93, 94 [mph], I’m average velocity, average spin rate, average movement. If I can be 2,600, I’m now average velocity with above-average spin rate and above-average movement. It takes my fastball from being the 17th-worst fastball in the league last year to one of the elite fastballs in the league. That massively changes my profile as a pitcher.

If I know my fastball is above-average, I can just throw the ball down the middle and trust that he’s going to [swing and miss] or pop up. So, it massively changes outcomes of games. It changes, like I said, financial compensation down the road for pitchers, especially as more teams are starting to look at spin rate and use that as a definitive factor. I mean, there’s relievers in the league right now who are getting picked up and put in the big leagues strictly because they have extremely high fastball spin rates. What if that guy had an average spin rate, but he decided to use sticky stuff for whatever reason? Now he gets a job over the guy who’s doing it legally. What if a guy uses sticky stuff to increase his spin rate his entire career? Now he has a reputation of being a super-high spin rate guy. He’s compensated in free agency because he has a super-high spin rate or because the numbers he produced have been way better due to the fact that his spin rates are so high due to him using a foreign substance. How’s that fair?

SN: When you started studying all this stuff, the research, what was the motivation? Was it looking for an edge, was it just curiosity?

TB: Looking for an edge. That’s how I choose to approach my career. I’m constantly trying to find an edge and find the next way to improve myself.

Five years ago, I realized that spin rate was such a huge issue. I was chasing the golden goose. I’ve chased it for five years and not a single thing that I’ve found other than velocity — if you throw harder, your spin rate goes up — that’s why comparing Bauer Units — that’s the name of RPM over miles per hour — it normalizes everybody. So, you can take a guy’s who’s 88 and a guy who’s 98 and compare their ability to spin the ball regardless of velocity. If you can increase the Bauer Units, you have a much more effective pitch.

I want to make my fastball better. How do I high-grade my fastball to make it the best fastball in the league? I can only throw so hard. I’m close to my genetic ceiling on my velocity.

I can’t just throw harder all of a sudden. I worked my ass off to create that — my velocity ticks up gradually every year, but by like 0.2 miles per hour or something. That’s not enough to offset the rise in average league velocity. As my velocity goes up, the league average velocity goes up and so my velocity stays relatively average compared to the league.

SN: When it comes to the sticky stuff and Major League Baseball, do you expect anything to change one way or another, whether it’s enforced or legalized?

TB: I hope it does. I’m not convinced that it will. I have no delusions about the situation. It’s not something that they want to address. It’s not something they want public. It’s part of why there’s been such backlash on me making it public. No one wants to talk about it, but it needs to be talked about, especially as teams use this information more and more to evaluate players and sign players and stuff like that. It creates a massively unfair playing field.