NBA trade season got off to an early start in the summer of 2021, with the Boston Celtics and Oklahoma City Thunder swapping former All-Stars. As the NBA moves toward the 2021 NBA draft in July and 2021 free agency in August, expect there to be many more deals.

With multiple superstars signing contract extensions over the past year, the free agent class of 2021 isn't as star-studded as previously expected. Will that mean teams looking to shake up their roster will try to make a trade for superstar players, like we've seen in past years with James Harden going to the Brooklyn Nets and Paul George going to the LA Clippers? If so, we'll have a rundown those deals -- plus every other trade that gets made -- right here, including grades from ESPN's Kevin Pelton.

MORE: Tradeable draft assets for all 30 teams

Two weeks after replacing Danny Ainge as president of basketball operations for the Boston Celtics, Brad Stevens made a seismic first move in his new role.

Boston Celtics get: C Al Horford C Moses Brown 2023 second-round pick

Oklahoma City Thunder get: PG Kemba Walker 2021 first-round pick (No. 16) 2025 second-round pick