Major League Baseball on Tuesday announced disciplinary action against five major and minor league players for betting on baseball, the latest indication that widespread legalization of sports gambling and MLB’s promotion of gambling-based advertisers could be heating the prevalence of gambling among players, long simmering out of sight, to a boil.

Infielder Tucupita Marcano, who is part of the San Diego Padres organization, became the first player to be declared permanently ineligible for betting on baseball since Pete Rose in 1989 after a league investigation revealed that Marcanobet bet more than $87,000 on MLB games, including 25 Pittsburgh Pirates games for which he was injured but on the major league roster.

The other four players – Oakland Athletics pitcher Michael Kelly, Philadelphia Phillies minor league infielder José Rodríguez, San Diego Padres minor league pitcher Jay Groome and Arizona Diamondbacks pitcher Andrew Saalfrank – were declared ineligible for one year after that investigation revealed they all placed bets on MLB games, too.

Groome, drafted in the first round of the draft by the Red Sox in 2016, played for the Portland Sea Dogs in the 2021 and 2022 seasons.

“The strict enforcement of Major League Baseball’s rules and policies governing gambling conduct is a critical component of upholding our most important priority: protecting the integrity of our games for the fans. The long-standing prohibition against betting on Major League Baseball games by those in the sport has been a bedrock principle for over a century,” MLB Commissioner Rob Manfred said in a statement.

“We have been clear that the privilege of playing in baseball comes with a responsibility to refrain from engaging in certain types of behavior that are legal for other people. Since the Supreme Court decision opened the door to legalized sports betting, we have worked with licensed sports betting operators and other third parties to put ourselves in a better position from an integrity perspective through the transparency that a regulated sports betting system can provide. MLB will continue to invest heavily in integrity monitoring, educational programming and awareness initiatives with the goal of ensuring strict adherence to this fundamental rule of our game.”

MLB, which was quick to allow its teams and national broadcasts to run betting odds and ads for online betting companies during games once the Supreme Court paved the way for legal sports betting, insisted in a news release Tuesday that none of the players involved influenced the outcomes of games on which they bet and that “the betting data does not suggest that any outcomes in the baseball games on which they placed bets were compromised, influenced, or manipulated in any way.”

The release explained that in March of this year, a legal sports betting operation flagged past betting from minor and major league players for MLB, which then obtained the data about their bets. The league has long been clear about its stance on sports betting: Players can place bets on other sports as long as they do so through legal betting operations, but they cannot, under any circumstances, bet on baseball.

Marcano last played in the majors in July 2023, when an ACL injury ended his season with the Pittsburgh Pirates. In total, MLB found he bet approximately $150,000 on baseball beginning in October 2022 and continuing through the summer of 2023. It was during that summer when he was on the injured list, but still receiving treatment at PNC Park, that he placed 25 bets on the Pirates. He did not appear in any of those games.

The other four players did not bet on teams for which they were rostered at the time, though some did bet on games played by their affiliated major league organization while playing in the minors. When Kelly was a minor leaguer in the Houston Astros system in 2021, he placed over/under bets on how many runs the big league team would score and how many strikeouts individual pitchers would have, according to MLB. Kelly, who has since appeared in 48 major league games with the Phillies and A’s, including 38 this year, was not involved in any of the games on which he bet.

The same was true of Saalfrank, a young lefty who pitched in three World Series games for the Diamondbacks as a rookie in 2023. MLB’s investigation found Saalfrank bet on MLB games 28 times while in the lower levels of Arizona’s minor league system. Four of those games were Diamondbacks games, per MLB, which said Saalfrank only won five of those bets.

Rodríguez, who appeared in one major league game with the Chicago White Sox before being acquired by the Phillies before this season, placed seven bets on the White Sox while a member of their Class AA team in Birmingham in 2022. In total, he bet approximately $750 over 28 bets on baseball.

Padres lefty Groome has yet to make his major league debut, but was found to have bet on the scores of Boston Red Sox games while he was a member of their high Class A affiliate in 2020 and 2021. According to MLB’s investigation, Groome bet $453.74 on 30 MLB game-related bets and had lost $433.54.

That Marcano’s name will now sit alongside Rose’s in the list of modern-day players banned for betting on baseball serves as a reminder both of the gravity of this offense in MLB’s eyes and the complicated place Rose occupies in baseball history because of his.

Rose had long since become MLB’s all-time hits leader by the time he was accused of betting on 52 of his team’s games while managing the 1987 Reds.

Rose, who would have had control over in-game decisions that could have helped him win bets if he had chosen to make them, denied those allegations. But he eventually accepted a lifetime ban in exchange for then-commissioner Bart Giamatti not issuing any formal findings about the extent of his gambling activities.