The agreement between head coach Doc Rivers and the Los Angeles Clippers is being delayed due to the language in Rivers' contract and the NBA's pending approval, according to ESPN. ESPN previously reported Monday that the league had already approved the Clippers acquisition of the former Boston Celtics coach.

Sources told ESPN on Sunday that Rivers agreed to a three-year, $21 million contract. As compensation for allowing Rivers out of his previous three-year deal, the Celtics will receive Los Angeles' 2015 first-round draft pick.

However, a proposed transaction that would have sent Kevin Garnett to the Clippers in exchange for DeAndre Jordan is on hold after commissioner David Stern spoke out against NBA teams being prohibited from making "side-trades".

A source confirmed to ESPN that the league plans to block any trade involving Garnett to Los Angeles as they believe it would be a violation of NBA rules.

Celtics forward Jeff Green confirmed Rivers decision to leave after speaking with his former coach over the phone. Green said that Rivers called him to let him know of his departure, which the forward understands "this is a business."

"I can't speak for the other guys, but I'm not angry at all," Green told ESPN's Jackie MacMullan. "I'm happy for him."

The Boston Celtics plan to enter a rebuilding stage and will do so with a new head coach for the first time since Rivers' hire in 2004. Rivers led the Celtics to an NBA championship in 2008 and an Eastern Conference Championship in 2010.

Under Rivers, the Celtics made the playoffs during the past six consecutive seaons, successfully capturing five straight Atlantic Division titles from 2007-08 to 2011-12.