Deal between Clippers and Celtics very close to the end

The Los Angeles Clippers and Boston Celtics reopened trade talks Wednesday and have quickly made progress toward separate transactions that ultimately would send both Celtics star forward Kevin Garnett and coach Doc Rivers to Los Angeles, according to sources close to the process.

Sources told ESPN.com that the Clippers, despite taking another break from the discussions Wednesday night so owner Donald Sterling could meet face-to-face with Rivers' fellow coaching candidate Brian Shaw, have relented on their previous unwillingness to surrender only one first-round pick to the Celtics to convince Boston to let Rivers out of the final three years, $21 million on his coaching contract.

After meeting with Shaw, the Clippers' front office met separately with Sterling to review all of the candidates and options, sources told ESPN.

One source close to the process expressed optimism the sides would reach an agreement in principle by Thursday on the two deals involving Garnett and Rivers, which the Clippers believe will all but cement the signature of star guard Chris Paul when Paul becomes an unrestricted free agent on July 1.

Although sources stressed that final details were still being worked out, one trade would be a straight player swap sending Clippers center DeAndre Jordan for Garnett, with the second move calling for Boston to receive two first-round draft picks as compensation for freeing Rivers from his Celtics contract.

However, ESPN.com has learned the teams will have at least one more hurdle to clear even if they finally agree to a trade framework after days of talks and multiple breakdowns in discussions.

Sources say the Clippers and Celtics, to push the trade through, will have to convince the league office that the deals were not contingent upon each other. According to NBA rules, side agreements or contingencies are prohibited in any trade or free-agent signing. Rules also prohibit coaches from being traded; teams can convey cash or draft picks as compensation to get a coach under contract released from those obligations.

It's thus believed that -- before any agreements between the Celtics and Clippers can be submitted to the league for the standard trade call to ensure that all the particulars meet the standards of the NBA's collective bargaining agreement -- both teams will have to prove the transactions are not essentially one trade.

The Clippers walked away from the bargaining table Tuesday morning because they were unwilling to part with two first-round draft picks for Rivers and likewise determined not to take back a player with a long-term contract -- such as Courtney Lee or Jason Terry -- as part of the Garnett deal. But L.A. re-engaged the Celtics in talks Wednesday afternoon, with sources saying Paul was among the strongest voices in the organization pushing for the deals to go ahead.