Sources: Clips-Celtics talks back on

As the Los Angeles Clippers and Boston Celtics seemingly inched closer to an agreement that would bring an end to their on-again, off-again negotiations and finally send both Celtics star forward Kevin Garnett and coach Doc Rivers to Los Angeles, sources close to the process said Thursday that a hurdle at league level threatens to scuttle the talks yet again.

Sources told ESPN.com that it has been communicated to both teams by the league office that the NBA has questions about the proposed transactions involving Garnett and Rivers and the appearance that they are connected.

The teams awoke Thursday, sources said, close to an agreement on separate transactions that would land Garnett and Rivers in Los Angeles. The first is a proposed one-for-one player swap that would send Clippers center DeAndre Jordan to Boston for Garnett, who would waive his no-trade clause to clinch the deal. The second move would require the Clippers to convey two first-round picks to Boston as compensation for the Celtics agreeing to let Rivers out of the three years and $21 million left on his contract.

League rules not only prohibit coaches from being formally "traded" but likewise prevent teams from making any trade or free-agent signing with contingencies or side deals attached. So it is incumbent on the Celtics and Clippers to convince the league office that these transactions would be made independently.

"I would say in the language of diplomacy that the teams are aware that the collective bargaining agreement doesn't authorize trades involving coaches contracts," NBA commissioner David Stern said on the "Stephen A. Smith Show" on ESPN Radio on Thursday. "The only consideration that can be done here in players transactions are other players, draft picks and a very limited amount of cash. But, coaches contracts don't qualify as extra consideration or acceptable consideration in player transactions. The teams know that ... it has been confirmed to them. What we wouldn't prohibit ... what the rules wouldn't prohibit ... Let me start again ... what the rules won't allow ... it can't be gotten around by breaking it up into two transactions."

One source with knowledge of the talks told ESPN.com on Thursday that the Celtics and Clippers have been negotiating for days knowing that league rules could well prohibit the transactions from going through.

Another source connected to the talks said Thursday that the Celtics and the Clippers, in the wake of ESPN.com's report about the league's concerns, have begun discussing alternative trade constructions to address any potential misgivings from the NBA.

ESPN.com reported Wednesday that the Clippers, despite taking an evening break from the discussions so owner Donald Sterling could meet face to face with Rivers' fellow coaching candidate Brian Shaw, had quickly made progress with the Celtics after re-opening talks and relenting on their previous unwillingness to surrender only one first-round pick to persuade Boston to let Rivers become a coaching free agent. League rules do allow teams to offer draft picks or cash to get a coach under contract released from those obligations.

After meeting with Shaw, Clippers officials met separately with Sterling late Wednesday to review all the candidates and options, sources told ESPN.com.

One source close to the process came away from Wednesday's developments expressing 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. Yet it remains to be seen, sources said, how big a hurdle this is and whether the teams will be able to get league approval on the current proposed framework of the two deals or be forced to propose alternatives.

The Clippers' Jordan, in an appearance on ESPN Radio's "Mike and Mike in the Morning" on Thursday, said he understands "it's a business" and wouldn't have any hard feelings for the team that drafted him if he's shipped out.

"I've been with the Clippers since I was 19," Jordan said. "That's all I know. I love L.A., I love the Clippers, I love my teammates and everything we stand for. [But if he's traded] I'll still be doing the thing I love, and that's playing basketball every day. No matter what team I'm on, I'll still be having a great time."

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.

The arrivals of Garnett and Rivers would be the first steps in the Clippers' plan to clinch Paul's signature on a new deal in July. As ESPN.com reported last week, L.A. also intends to make every attempt to sign Paul Pierce away from the Celtics as well if it's successful in acquiring Garnett and Rivers, although that likely depends on Pierce's ability to join Paul in free agency July 1.

Clippers longtime broadcaster Ralph Lawler tweeted late Wednesday night: "Just spent better part of the evening w/Cris [sic] Paul and his wife Jada. I can only tell you that he is a Big fan of Doc Rivers."

The Celtics must decide by June 30 whether to pick up Pierce's $15.3 million option for the 2013-14 season or buy him out for $5 million. Rival executives expect Boston to try to trade Pierce by month's end if Garnett and Rivers leave in hopes of getting something for their longest-tenured player, with the team that acquires Pierce potentially setting him free before June 30 to get the $10 million in salary-cap savings.

Rivers and Celtics president of basketball operations Danny Ainge met Wednesday evening in hopes of settling the coach's future with the club, sources said. No resolution was reached, but Rivers has told associates that he expects to have an answer soon, possibly as early as Thursday morning.

Ainge repeatedly has insisted the team's preference is for Rivers to remain as coach, even after negotiations to allow him to leave for the Clippers broke down Tuesday morning. But sources with knowledge of Rivers' thinking maintain he no longer wants to coach the Celtics if the team wants to go young.

"He wants another championship or at least another chance at it," one source close to Rivers said. "He doesn't want to go through a rebuilding process."

Rivers' preference, sources said, is to coach next season. He also would have the option of returning to broadcasting if he did not want to continue with the Celtics and an exit to the Clippers could not be facilitated.

The Clippers, meanwhile, proceeded with second interviews with Byron Scott and Shaw on Tuesday and Wednesday, respectively, to guard against another collapse in the talks to secure the services of Rivers.

But one team source insists the Clippers have committed to pay Rivers a salary commensurate with what he was making in Boston and had, in fact, already agreed to that aspect of the deal. Rivers is entering the third season of a five-year, $35 million coaching contract with the Celtics.

The Clippers, despite Sterling's frugal reputation, are willing to pay Rivers an equal $7 million per year for five years, sources insisted to ESPN.com.

ESPN.com's Chris Broussard and ESPNLosAngeles.com's Arash Markazi contributed to this report.