Sources tell ESPN.com that the Celtics and the Mavericks have an agreement in principle to send the All-Star point guard to Dallas for Brandan Wright, Jae Crowder, Jameer Nelson and draft picks. The Celtics will receive a first-round pick in the 2015 draft and a second-rounder in 2016, sources said.
The possibility exists that other players will be added to the final deal, but a Rondo-to-the-Mavericks deal is expected to be completed Thursday night.
Parsons addressed the possibility of playing with Rondo on 103.3 FM ESPN in Dallas on Thursday.
"To be able to get a guy like Rondo, it's unbelievable," he said. "It's not every day that you can get a point guard of his status, and the way he can pass the ball, he's a difference-maker. To be able have that, with the combination of what we already have with our system and the players put around him, it's special. It's definitely exciting. Like I said, I hope it goes through because he's a heck of a talent, one of [the] better point guards in the NBA."
Las Vegas sports book operator CG Technology shortened Dallas' odds to win the NBA title Thursday, moving the Mavericks from 13-1 to 8-1 after news broke that the deal is close to being finalized.
Rondo, who is in the final year of his current contract, has left little doubt in recent months that he intends to test the market as a free agent in July. But sources say Dallas, amid growing concern about its point guard play and sensing the opportunity to acquire a top-flight player it has coveted for some time, is confident it could win over Rondo for the long term.
Boston has the necessary trade exceptions to absorb all the salaries from Dallas while potentially generating a valuable $12.9 million trade exception (Rondo's 2014-15 salary) to help with future roster construction.
The Celtics were at the roster maximum of 15 before the trade and will need to part with additional players to absorb three from Dallas.
The Mavericks were one of several teams to express interest in Rondo. The Celtics also had talked to teams including the Sacramento Kings, New York Knicks, Los Angeles Lakers and Houston Rockets about a potential deal, according to sources.
Rondo is averaging 8.3 points and 10.8 assists per game this season, his ninth in the league.
ESPNBoston.com's Chris Forsberg and ESPN.com's David Purdum contributed to this report.