While the Boston Celtics believe Jaylen Brown is fully deserving of his massive contract extension, NBA legend Rick Barry believes otherwise.

Brown signed the richest contract in NBA history when he put pen-to-paper on a five-year, $304 million supermax extension with the Celtics last month, and Barry believes the franchise is massively overpaying the veteran.

Barry told Joy De'Angela:

"You look at some of the contracts they have, like Brown, $306 million. I mean, that's just hard for me to believe. You know what his average in the playoffs for them is 18.5 points a game. I mean, 18.5 points a game, and he's going to make $69 million in the last year of his contract. But 18.5 points a game, that's nothing. Seriously.

"To pay somebody that kind of money, and he's a nice player, I really like him, but man, he's got to improve his game. He turns the ball over too much, he tries to force things, and so is his teammate [Jayson] Tatum. That's one of the reasons they lost to the Warriors two seasons ago. They make too many turnovers."

Brown put together the best season of his career in 2022-23, averaging 26.6 points, 6.9 rebounds and 3.5 assists in 67 games while shooting 49.1 percent from the floor and 33.5 percent from deep. However, he also averaged 2.9 turnovers per game.

The 26-year-old's numbers also dipped in the playoffs as he averaged 22.7 points, 5.6 rebounds and 3.4 assists in 20 games while shooting 49.6 percent from the floor and 35.4 percent from deep. He also averaged 3.3 turnovers per game.

Turnovers have long been an issue in Brown's game. He's averaging 2.0 turnovers per game in the regular season across his seven-year career and 2.2 turnovers per game in the playoffs.

There's a lot of room for improvement in Brown's game, but given he's only 26, the Celtics must feel he'll be able to iron out his inefficiencies over the course of his new contract.