On Wednesday, the NBA announced that Jontay Porter, a two-way player who recently came under contract with the Toronto Raptors, has been banned from the league for his illicit involvement in sports betting, including intentionally underperforming.

According to the NBA, the 25-year-old leaked confidential information to sports bettors, held back in at least one game while with the Raptors, and bet on NBA games while playing in the league—all contractual violations that have now resulted in his ban from the NBA.

“There is nothing more important than protecting the integrity of NBA competition for our fans, our teams and everyone associated with our sport, which is why Jontay Porter’s blatant violations of our game rules are being met with the most severe punishment,” NBA commissioner Adam Silver said while announcing the ban.

The league also said its investigation remains open and may result in further findings.

In addition to the contractual infringement, Mr. Porter’s gambling-related actions may constitute violations of state and federal law. The NBA said it was sharing the information it obtains with federal authorities.

The NBA began its investigation in late March after licensed sports betting operators and an organization that monitors legal betting markets noticed irregular bets being placed on Mr. Porter’s performance during a March 20 game.

The NBA’s investigation found that Mr. Porter disclosed confidential information about his own health to an individual he knew to be an NBA bettor shortly before the Raptors’ March 20 game against the Sacramento Kings.

Another bettor Mr. Porter was familiar with then placed an $80,000 same-game parlay bet that would yield $1.1 million if Mr. Porter underperformed in the game. Sure enough, Mr. Porter left the game after three minutes, claiming to feel ill, according to the NBA.

Sportsbooks found the coincidence suspicious, and the $80,000 bet was frozen.

The league’s investigation also found that Mr. Porter placed at least 13 bets on NBA games using an associate’s online betting account. These bets ranged in size from $15 to $22,000, for a total of $54,094, according to the NBA.

The total payout from these bets was $76,059, resulting in net winnings of $21,965. None of the bets involved any game in which Mr. Porter played himself. Three of the bets were multi-game parlay bets that included one Raptors game, in which Porter bet that the Raptors would lose. All three bets lost, the NBA reported.

Mr. Silver, the first major U.S. sports league commissioner to publicly advocate for the legalization of sports betting, reiterated that the transparency of legal betting facilitates identifying suspicious activity but added that the case of Mr. Porter showed that more needed to be done.

“This matter also raises important issues about the sufficiency of the regulatory framework currently in place, including the types of bets offered on our games and players,” he said.

“Working closely with all relevant stakeholders across the industry we will continue to work diligently to safeguard our league and game.”