The Los Angeles Clippers and Boston Celtics on-and-off trade saga continued Thursday as both sides reportedly came closer to reaching an agreement to send coach Doc Rivers and forward Kevin Garnett to Los Angeles. However, the biggest hurdle may now be NBA.

The league has informed both franchises that they have questions about the proposed trade, sources told ESPN.com. According to ESPN, both teams were close to reaching an agreement on the proposed deal in two separate trades.

The first trade proposed involves Boston sending Garnett to the Clippers in exchange for center DeAndre Jordan, who would waive his no-trade clause. The teams would then agree to a deal that sends Rivers to Los Angeles in exchange for two future Boston first-round picks. Los Angeles would receive the draft picks as compensation for Rivers being allowed out of his three year contract.

NBA rules do not allow a coach to be "traded" and also prevent teams from making trade or free-agent transactions with side deals attached, which forces both sides to convince league officials that the moves would be made separately.

A source close to the negotiations told ESPN Thursday that the two teams have been in talks for days with knowledge that league rules could potentially halt the move. Another source added that the franchises have began working on alternative moves in wake of ESPN's report of the league's questioning regarding the trade talks.

Los Angeles interviewed former Cavaliers coach Byron Scott on Tuesday night. Clippers officials also met with former Pacers assistant Brian Shaw on Wednesday, then met separately to discuss all the candidates considered.