Major League Baseball could be headed for a sticky showdown with some of its best pitchers if allegations of an illegal ball-gripping substance prove true.

Former Los Angeles Angels employee Brian Harkins, who was fired by the team last March, said in court papers filed in California last week that multiple Cy Young winners and All-Star pitchers have used an illegal substance that he provided.

According to the Los Angeles Times, Harkins named a number of former and current Angels, and also said he has evidence suggesting superstars Gerrit Cole (New York Yankees), Justin Verlander (Houston Astros), Adam Wainwright (St. Louis Cardinals) and Felix Hernandez (Atlanta Braves) have all used the substance to improve their grip on the ball.

The evidence surrounding Cole, who signed a record nine-year, $325 million deal with the Yankees last season, is particularly damning. A text message in which the player identifies himself and asks Harkins for help "with this sticky situation "was included in the evidence submitted to the court.

Harkins, 55, worked for the Angels for 38 years but was fired after the club determined he was making and distributing an illegal substance to visiting players. He filed a defamation lawsuit against the team and MLB in August.

According to his lawyer, Harkins contends the Angels tried to protect their players and MLB didn't want to deal with another scandal following the Houston Astros' sign-stealing scandal.

His lawyer added that Harkins will seek at least $4 million if the case goes to trial.

MLB rules governing what pitchers can and can't do to the baseball are long-winded but simple: "No player is permitted to intentionally damage, deface or discolor the baseball by rubbing it with any type of foreign item or substance, including dirt or saliva."

While the rules are designed to prevent scuffing or spitballs, which have long been known to have unnatural movement, there's traditionally been a gray area concerning the use of sticky stuff－usually pine tar－to get a better grip.

But as Sports Illustrated's senior baseball writer, Tom Verducci, explained following an investigation in 2018: "Pitching labs have figured out there is a way to improve the spin rate of the ball: Load up pine tar or a similar sticky substance on your fingers. With more tackiness, you can create more spin. Applying a bit of pine tar to your fingers is an accepted practice－enough so that the baseball is not slick－but applying too much or too conspicuously is verboten."

As for why pitchers should want their pitches to spin as much as possible, a greater spin rate equals better movement and increased deception.

Trevor Bauer, who dramatically increased his spin rate en route to winning the National League Cy Young Award for the Cincinnati Reds in 2020, estimated in an interview last spring that roughly 70 percent of pitchers use pine tar to get a better grip on the ball.

Harkins' lawsuit suggests science has now come up with something much more effective.

According to USA Today, Harkins said Verlander, a two-time Cy Young winner who has appeared in eight All-Star games, told him in a phone conversation that "MLB had learned teams 'hired chemists' and commissioned studies 'to come up with stuff more advanced (than pine tar) to create spin rate', and are using that proprietary information to lure free-agent pitchers".