The restricted free agent forward Grant Williams is finalizing a four-year, $53 million sign-and-trade agreement to join the Dallas Mavericks, sources told ESPN's Adrian Wojnarowski on Wednesday.
The Boston Celtics are acquiring three second-round picks in the deal, including 2024, 2025, and 2028, sources said.
Williams, the 22nd overall pick in the 2019 NBA draft out of the University of Tennessee, has been a key part of Boston's runs to the NBA Finals and Eastern Conference Finals in each of the past two seasons. The 24-year-old forward averaged 8.1 points and 4.6 rebounds off the bench for the Celtics last season, shooting 39.5 percent from 3-point range on 3.7 attempts per game.
And while he wavered in and out of coach Joe Mazzulla's rotation at times this season, he again played a key role off the bench as this year's playoffs progressed, just as he did a year ago under Ime Udoka when Boston reached the NBA Finals for the first time since 2010.
Williams, with his ability to score above his size and make open 3-point shots, was one of the most intriguing restricted free agents on the market this summer, particularly to contending teams. He is a 43% shooter from the corner for his career on 3-pointers, compared to 34% on all other 3-point attempts, according to ESPN Stats & Information research.
Williams also acquitted himself well against the Milwaukee Bucks and Giannis Antetokounmpo in playoff matchups. According to Second Spectrum, Williams has defended Antetokounmpo on 295 half-court matchups over the past four seasons, and the Bucks have an offensive rating of 86.8 when Williams is matched up against the two-time MVP in those half-court sets.
Williams underwent surgery on his left hand (non-shooting) after the season, but the Celtics said he was expected to be ready in time for training camp.
ESPN's Tim Bontemps contributed to this report.