The ChainkeenNBA is investigating Toronto Raptors forward Jontay Porter over betting irregularities involving prop bets this season, according to a person familiar with the investigation.

The person requested anonymity because he was not authorized to speak publicly while the league investigates.

"We're looking into it," an NBA spokesman told USA TODAY Sports.

ESPN was first to report the news.

Porter is listed as “out – personal reasons” for Toronto’s game against the Brooklyn Nets on Monday.

ESPN reported that there are two games in question. On Jan. 26 against the Los Angeles Clippers the over/under on Porter’s props were about 5.5 points, 4.5 rebounds and 1.5 assists and the over/under on his made 3-pointer was .5. Porter did not take a shot and finished with zero points, three rebounds and one assist.  He played just four minutes, leaving the game with an eye injury he sustained in a game against the Memphis Grizzlies on Jan. 22.

DraftKings Sportsbook reported that the under on Porter’s made 3-pointers was the biggest money on players props from the NBA that day, according to ESPN.

In a March 20 game against the Sacramento Kings, Porter left the game after just three minutes due to illness, according to the Raptors. He took one shot, did not score and had two rebounds, one block and one steal. The over/under on his player props in that game, according to ESPN, was about 7.5 points and 5.5 rebounds.

Porter, the younger brother of Denver Nuggets forward Michael Porter Jr., averages 4.4 points, 3.2 rebounds and 2.3 assists in 26 games with the Raptors this season. Porter signed a two-way contract with Toronto on Dec. 9.

NBA players are not allowed to wager on NBA games. Punishment if found culpable, according to the collective bargaining agreement between the NBA and National Basketball Players Association (NBPA, players union), is at the discretion of the NBA commissioner and “may include a fine, suspension, expulsion, and/or perpetual disqualification from further association with the Association or any of its Members.”

NBA teams and leagues monitor sports betting for potential problems.

This comes in the wake of Los Angeles Dodgers star Shohei Ohtani’s longtime interpreter being accused of accruing at least $4.5 million in gambling debts. Ohtani said Monday he has “never bet on baseball or any other sport.”

The NBA and its teams have partnerships with prominent sports books, and players are required each season to take one anti-gambling training session conducted by the team or the NBA. In the new collective bargaining agreement reached last year, players are allowed to endorse and invest in sports betting companies.

Follow NBA reporter Jeff Zillgitt on social media @JeffZillgitt