Toronto Raptors forward Jontay Porter is under investigation by the NBA following multiple instances of betting irregularities over the past several months, multiple sources told ESPN on Monday.

At issue are prop bets involving Porter from games on Jan. 26 and March 20, multiple sources told ESPN. An NBA spokesman told ESPN that the league is "looking into it."

In the game on Jan. 26 against the LA Clippers, there was increased betting interest on the under for Porter props, which for the night were set at around 5.5 points, 4.5 rebounds and 1.5 assists. There was also an over/under for Porter's made 3-pointers, which was 0.5.

That evening, Porter played just four minutes before leaving the game because of what the Raptors said was an aggravation of an eye injury he had suffered four days earlier against the Memphis Grizzlies. Porter did not score against the Clippers but had three rebounds and one assist, and he did not attempt a 3, meaning the under hit on all of the props.

The next day, as part of a daily report to users on betting results, DraftKings Sportsbook stated that the under on Porter's 3-pointers was the biggest money winner for bettors of any NBA player props from games that evening.

Porter played 19 minutes two days later and scored 12 points with 7 rebounds and 3 assists.

On March 20 against the Sacramento Kings, Porter played just three minutes before exiting because of what the Raptors said was an illness and did not return. He did not score after attempting one shot and had two rebounds.

Sportsbooks had his over/unders set at around 7.5 points and 5.5 rebounds.

The next day, DraftKings Sportsbook reported in a media release that Porter's prop bets were the No. 1 moneymaker from the night in the NBA.

At least one other U.S. sportsbook detected unusual betting interest on the Porter props in the games in question. A sportsbook industry source told ESPN that multiple betting accounts attempted to bet large amounts, upward of $10,000 and $20,000, on Porter unders in the January game against the Clippers. Betting limits on NBA player props vary by sportsbook and customer but are typically around $1,000 to $2,000.

"People were trying to do whatever they could to bet Jontay Porter props [against the Clippers]," the source said. "And then, just a few days ago, the same thing. We had a bunch of people trying to bet under for more."

Porter, the brother of Denver Nuggets star Michael Porter Jr., is on a two-way contract with the Raptors earning $415,000 this season.

He missed the Raptors' game on Saturday against the Washington Wizards for personal reasons, according to the team. He was also out for Monday's loss to the Brooklyn Nets for personal reasons.

Raptors coach Darko Rajaković said he became aware of the investigation shortly before Monday night's game.

"I never doubt injuries. I never doubt honesty from players," Rajaković said. "Obviously, I've never had a situation like this before."

He added that he had not discussed the matter with his team.

"I don't know their reaction," Rajaković said. "I just know nobody wants those kind of situations to happen to anybody, to any team. We've just got to deal with it."

NBA players, along with all league employees, are prohibited from betting on any NBA events, including prop bets. Violations of the policy could include fines, suspensions and possible termination of contracts, among other actions.

Sports betting is monitored by dedicated personnel from each NBA team, and the league has a team of data scientists focused on sports betting anomalies and possible integrity issues and also works with third-party integrity monitors.

Porter made his NBA debut in 2021, playing 11 games with the Grizzlies. In college at Missouri, he tore an ACL before his sophomore season and tore it again and an MCL while rehabbing in early 2019. He went undrafted and didn't play in the NBA over the previous two seasons. He signed with the Raptors in December.

Porter has played in 26 games this season, averaging 4.4 points, 3.2 rebounds and 2.3 assists in 14 minutes a game.

The Associated Press contributed to this story.