6/4 7:20 AM -- Tucupita Marcano has been banned from Major League Baseball for life, officials announced Tuesday.

The league released a statement on the decision ... saying it was determined Marcano placed 387 baseball bets, including 231 related to MLB, in 2022 and 2023 -- totaling more than $150,000 on the sport.

The league added Marcano bet on the Pirates 25 times while he was a member of the organization -- although he did not play in any of the games due to his season-ending injury.

Marcano lost all of his parlays involving the Pirates and only won just over 4% of his MLB-related bets ... but despite his lack of success, rules are rules.

Four other players -- Athletics pitcher Michael Kelly and minor leaguers Jay Groome, Jose Rodriguez and Andrew Saalfrank were also banned one year for violating the league's betting rules.

Major League Baseball has yet another gambling scandal on its hands -- this time, involving a player accused of betting on his former team's games.

The Wall Street Journal broke the news on Monday ... reporting San Diego Padres infielder Tucupita Marcano is currently under investigation for violating the league's gambling policy.

Marcano -- who made his debut back in 2021 -- reportedly gambled on Pirates games while he was on the injured list for the team during the 2023 season.

Marcano is now a member of the Padres, but he has not stepped onto the diamond for San Diego this season ... as he is still recovering from an ACL tear.

MLB and its Players Association have yet to comment on the allegations ... but both sides are hashing out details about the potential punishment, according to the outlet.

The 24-year-old is facing a serious penalty -- a potential lifetime ban from the league -- and he may not be the only one to get the axe.

WSJ is also reporting four other pros could face discipline for betting on baseball while they were in the minor leagues.

This comes on the heels of the Ippei Mizuhara bombshell investigation ... in which the longtime interpreter admitted to stealing millions from Los Angeles Dodgers superstar Shohei Ohtani to pay off his gambling debts to an illegal sportsbook

While that situation did not involve a player ... it was nevertheless a bad look for the league.