By Matt McCarthy,

The Boston Celtics have made a major commitment in their future, signing guard/forward Jaylen Brown to a four-year, $115 million contract extension.

The news broke about an hour before the deadline for the two sides to come to an agreement. ESPN’s Adrian Wojnarowski was the first to report the signing.

The signing makes Brown one of the top-25 highest-paid players in the NBA.

This marks the first time Celtics President of Basketball Operations Danny Ainge has signed a player on a rookie contract to an extension since Rajon Rondo in 2009. The agreement was negotiated over the weekend, according to Wojnarowski.

Had the Celtics and Brown not struck a deal by 5 p.m. Monday, Brown would have become a restricted free agent next summer.

Brown, the third overall pick in the 2016 NBA draft, averaged 13 points per game last season.

In a statement, Ainge lauded Brown for his performance in his first three NBA seasons and called the 22-year-old a “major part” of the team’s title aspirations.

“Jaylen has made tremendous strides over the last three years and has become a fantastic player for us on both ends of the court,” Ainge said. “He’s a great person and hard worker who, at 22 years old, can score and defend against the best players in the NBA. Jaylen is a true professional who did a great job accepting his role last season, and he is a major part of our championship goals.”

You can hear Matt McCarthy on various 98.5 The Sports Hub programs. Follow him on Twitter @MattMcCarthy985.