Getty Images

Despite the fact that he has only started in 16 games over his first three years with the franchise, the Boston Celtics have obviously been happy with what they've seen from center Robert Williams since selecting him in the first round of the 2018 NBA Draft. The Celtics and Williams agreed to a four-year, $54 million contract extension on Friday, according to ESPN's Adrian Wojnarowski. The deal will keep Williams under team control through the 2025-26 season. 

Williams' role with the Celtics has continued to expand since his rookie season. He started in two games and played just 8.8 minutes per game as a rookie. His playing time increased to 13.4 minutes per game during his sophomore season. Last season, he started in 16 games for Boston and averaged 8.0 points, 6.9 rebounds, 1.8 assists and 1.8 blocks in 18.9 minutes per performance. Clearly, the Celtics view him as a big piece of the puzzle moving forward. 

The extension for Williams is the latest move in what has been a busy summer for the Celtics under the stewardship of new general manager Brad Stevens. In addition to Williams, Boston has also signed veteran guard Marcus Smart to an extension, traded for Al Horford and Josh Richardson, and signed Enes Kanter and Dennis Schroder in free agency. They also hired Ime Udoka to be the team's new head coach following Stevens' move to the front office. 

"I want to be a team that Boston can really get behind, that plays with a great edge, that plays with a grit and toughness that's necessary to compete at the very, very high level," Stevens said of the '21-22 iteration of the Celtics earlier this week. "I think Ime and his staff will do a great job coaching to that."  

Williams will share time at the center spot with Horford and Kanter next season, though Williams should probably be penciled in as the starter given his age and upside. Plus, the Celtics went 10-3 in the games that Williams started last season. Expect Boston to look to build off of that moving forward.