Major League Baseball (MLB) on Tuesday suspended Padres infielder Tucupita Marcano for life for betting on games. He was suspended along with four other players - who received one-year bans - after they were found to have placed non-baseball bets through a legal sports book.

Also implicated was Oakland Athletics pitcher Michael Kelly, along with minor league players who were suspended for one year for betting on baseball games, MLB said.

"Strict enforcement of Major League Baseball's rules and policies regarding gambling conduct is a critical component of maintaining our most important priority: protecting the integrity of our games for our fans," MLB Commissioner Robert Manfred said in a statement.

"The long-standing prohibition against betting on Major League Baseball games by those within the sport has been a bedrock principle for more than a century," Manfred said. "We have been clear that the privilege of playing baseball comes with the responsibility to refrain from participating in certain types of behaviour that are legal for others."

This is the biggest betting scandal to hit the sport in decades. MLB detailed that between October 2022 and last July and November, Marcano placed 387 baseball bets worth more than $150,000 (€138,000) through a legal sports book. The bets included 231 on MLB games, totalling $87,319 (€80,323) of the $150,000.

As a result, José Marcano, nicknamed Tucupita after his Venezuelan birthplace, is the first active player in a century to be banned for life for betting.

MLB said Marcano, who has been out this season recovering from ACL surgery, was declared "permanently ineligible" for violating the league's sports betting rules.

Marcano became the first active MLB player to be banned for life since New York Giants outfielder Jimmy O'Connell in 1924.

In 1989, MLB also banned Pete Rose, the game's all-time hits leader with 4,256, for betting on games after his playing career ended.

Marcano, who was playing for the Pittsburgh Pirates at the time, "did not appear in any of the games on which he bet," the league said.

"There is no evidence to suggest, and Marcano denies, that he compromised, influenced or manipulated the outcome of any baseball game on which he wagered."

The Pirates said they were "extremely disappointed in Marcano's actions", adding: "While the thorough investigation found no evidence that games were compromised, influenced or manipulated in this case, protecting the integrity of our game is paramount."

Kelly, the 31-year-old Oakland Athletics pitcher who has been suspended for one year, placed 10 bets totalling $99.22 (€91.27) on MLB games in 2021 while with a minor league affiliate of the Houston Astros, MLB said. He appeared in 28 games for the Athletics this year, pitching 31.1 innings with a 2.59 ERA. "Kelly did not appear in any of the games he wagered on and did not place any bets involving his assigned team," the league said.

The other three players involved are in the minor leagues: Dominican José Rodríguez (Philadelphia), Jay Groome (San Diego) and Andrew Saalfrank (Arizona). None of them bet more than $1,000. Saalfrank and Rodríguez have major league experience.

"The A's were disappointed to learn of the matter involving Michael Kelly," said a team statement. "This violation occurred prior to Michael joining the A's organisation, and we fully support MLB's sports betting policy."

Groome, 25, placed 32 MLB-related bets totalling about $450 (€413) in 2020 and 2021, none of which involved his team, MLB said.

Rodríguez, 23, wagered about $750 (€690) on 28 MLB games and three college baseball games in 2021 and 2022, none of which involved him as a player, MLB said.

Saalfrank, 26, bet $445(€409) on 28 MLB games and one college game and did not appear in any of the games he bet on.

MLB was rocked earlier this year by revelations that Shohei Ohtani's former interpreter stole nearly $17 million from the Los Angeles Dodgers star's bank account to pay gambling debts. 

Ippei Mizuharapleaded guilty to bank fraud and filing a false tax return, which could see the former friend and interpreter of the MLB megastar spend more than 30 years in prison.