The NBA is investigating whether a failed sign-and-trade agreement that would have sent Bogdan Bogdanovic from the Sacramento Kings to the Milwaukee Bucks happened earlier than league rules allow, sources confirmed to ESPN.

News of the league's investigation was first reported Thursday by The New York Times.

The NBA's free-agency period begins Friday. It was widely reported that Milwaukee and Sacramento had reached agreement in principle on a sign-and-trade deal Tuesday that would have brought Bogdanovic and Justin James to the Bucks, sources told ESPN. The Kings would have acquired versatile forward Donte DiVincenzo, D.J. Wilson and Ersan Ilyasova, sources said.

If the agreement occurred Tuesday, it would have been three days earlier than free-agent negotiations were permissible.

The Bucks and Kings hoped to bring Bogdanovic the framework of a sign-and-trade to negotiate a Bogdanovic contract with Milwaukee on Friday, according to sources. The deal fell through when Bogdanovic said later that he planned to enter restricted free agency.

On Thursday, the Kings extended Bogdanovic a $10.7 million qualifying offer, sources told ESPN's Adrian Wojnarowski, giving Sacramento the right to match any offer sheet Bogdanovic signs with another team.