The newest Celtics trade rumor suggests that free-agent guard Jason Terry is about to sign a three-year contract with Boston.

Jason Terry, a top NBA sixth man, stellar shooter, and winner of the league's 2009 Sixth Man of the Year Award, would be a great addition to the Celtics squad, which is facing the prospect of losing sharp-shooting superstar Ray Allen this off-season.

Jason Terry, who won a championship with the Dallas Mavericks last year, has reportedly been offered $5 million per year for the next three seasons, sources close to the situation told ESPN on Tuesday. The three-year, $15-million-deal can be finalized July 11, according to Yahoo! Sports.

Terry, who has played his last eight seasons in Dallas after replacing Steve Nash in 2004, is now a free agent, and reports that the Mavs, who are looking for salary cap space, are not planning to match Boston's offer.

Jason Terry, 35, was an integral part of the 2011 Mavericks team that won the franchise its first NBA championship. The situation in Dallas is getting very interesting, as the Mavericks are still waiting to hear whether Deron Williams will follow his Nets to Brooklyn, or whether he will sign with the Mavs. A source told ESPN that Jason Terry made his decision regarding Boston without the player knowing for sure what Williams' plans will be.

Jason Terry reportedly spoke with Boston president Danny Ainge and coach Doc Rivers on Sunday, the first day of NBA free agency this off-season, according to Yahoo! Sports. 

Terry averaged 15.1 points and 3.6 assists last season and shot 37.8 percent from the three-point range. Despite his status as less than that of a superstar player, Jason Terry is fourth on the NBA's all-time list for three-pointers made and has a career 38 percent three-point shooting percentage, according to ESPN.

Another top shooter, Celtics' star Ray Allen, is a free agent this year, and as such he is planning to visit the Miami Heat on Thursday and the Los Angeles Clippers on Friday, sources told ESPN The Magazine. The Celtics suffered a heartbreaking loss to the Heat in Game 7 of this year's Eastern Conference Finals, and many believe 2011-2012 was the end of the championship-winning Big Three Celtics era of Ray Allen, Kevin Garnett and Paul Pierce.

The future for Allen and Kevin Garnett, a Celtics star who may also leave the team, will be interesting to watch as the Boston Celtics we've grown accustomed to try to find the right players to bring home another NBA championship.