FanDuel and DraftKings are among the sportsbooks that will not offer 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.
The NBA is issuing a memo to all sportsbooks on the issue Friday, sources told ESPN.
FanDuel and DraftKings were among the sportsbooks that said they would be adhering to the NBA's request.
"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."
Sportsbooks flagged suspicious betting patterns on the under on Porter's statistics in games in January and March. Porter 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.
