Major U.S. sportsbooks on Friday said they would not be offering under bets on NBA players who are on two-way or 10-day contracts to combat attempts at manipulation.

The restriction is a result of discussions the NBA had with sportsbooks over the summer, after former Toronto Raptors forward Jontay Porter was banned from the league for his role in a gambling scheme centered on prop bets on his statistics.

FanDuel, DraftKings, BetMGM, ESPN BET and Caesars Sportsbook confirmed to ESPN on Friday that they planned to comply with the prop betting restrictions.

“We are pleased that these actions have been taken to help protect the integrity of our games,” an NBA spokesperson told ESPN.

FanDuel told ESPN that it is “always working with our partners to make sure the markets available adhere to their standards.” A DraftKings spokesperson said the sportsbook “is in alignment with the NBA and thankful for the opportunity to engage with them on the topic.” BetMGM also confirmed to ESPN that it would not offer under betting on prop wagers on select players.

Sportsbooks flagged suspicious betting patterns on the under on Porter’s statistics in games in January and March. Porter, who was on a two-way contract with the Raptors at the time, exited a Jan. 26 game against the LA Clippers and a March 20 game against the Sacramento Kings after playing just a few minutes.

Porter pleaded guilty to conspiracy to commit wire fraud July 10 and is scheduled to be sentenced Dec. 18 in New York.

Two-way contracts are given to players who go back and forth between the G League and the NBA. Ten-day contracts allow teams to add players for up to 10 days or three games.