BOSTON — In his first public comments since the shocking trade of Jaylen Brown, Boston Celtics president of basketball operations Brad Stevens said the decision to send the five-time All-Star to the Philadelphia 76ers was “a really hard call.”“We’ve lost a lot of sleep about it,” Stevens said. “And we understand that a lot of people have.”So why did the Celtics trade Brown, theoretically entering his prime at age 29, after the best season of his career?Stevens said that he believed his team needed to take a different path forward to maximize its chances of winning a championship again soon. Stevens said he thought the future looked “a little bit more challenging with 70 percent of our cap and such a high percent of our usage tied into two players (Brown and Jayson Tatum).”Why did the Celtics trade Jaylen Brown?Jay King and Jeshua KiddStevens said that Brown and Tatum combined to make 47 percent of the salary cap when the Celtics won the 2024 championship. That allowed the team to build out a deep, star-studded supporting cast. But many of those players are now gone after Stevens led an overhaul last season to push his team under the collective bargaining agreement’s second-apron threshold.