After spending the first four years of his career as a member of the Boston Celtics, former first-round pick Grant Williams decided to join the Dallas Mavericks in NBA free agency this offseason. Since he was a restricted free agent and wanted to leave Boston, these two teams came together to finalize a sign-and-trade deal that also involved a third team in the San Antonio Spurs.

Not only did Williams go to Dallas in this trade on a new four-year, $53 million contract, but veteran forward Reggie Bullock was traded from the Mavs to the Spurs along with a 2030 first-round pick swap. Both the Celtics and Mavs will be receiving two second-round picks each from this trade, according to ESPN's Adrian Wojnarowski.

Making the NBA Finals in 2022 and coming up one win shy of reaching the Finals again this past year, the Celtics had leaned on Williams as a key secondary talent on their bench. However, wanting to see his role expand and get compensated for what he's done, Dallas made the most sense for Williams.

Having the chance to come in right away and start out on the wing, this was too good of an opportunity for Williams to pass up on. In addition to the potential of seeing more playing time, the opportunity to make more money and play in a state where he would not be taxed heavily also factored into Williams' decision, league sources told ClutchPoints.

Playing in a total of 288 games with the Celtics over the last four seasons, Williams has averaged 6.2 points and 3.4 rebounds per game while shooting 37.9 percent from the floor for his career. Over the last two seasons in Boston, he has shot just north of 40 percent from the perimeter.

The Mavericks had been searching for a defensive-minded forward that could compliment the play of their superstars in Luka Doncic and Kyrie Irving by playing off-the-ball on the offensive end of the floor as well. They had shown a level of interest in Portland Trail Blazers restricted free agent Matisse Thybulle and he even agreed to an offer sheet. However, Portland was not about to let Thybulle go this offseason and they matched the Mavs' in order to keep the young wing.

Emerging as a target of theirs early on in the offseason, Williams now becomes an essential secondary contributor in Dallas that will aid them on both ends of the floor.