Celtics trading Kemba Walker, first-round pick to Thunder for Al Horford, Moses Brown

In Brad Stevens’ first major move since replacing Danny Ainge as president of basketball operations, the Boston Celtics will trade guard Kemba Walker, a 2021 first-round pick and future second-round to the Oklahoma City Thunder for Al Horford, Moses Brown and a second-round pick, a person familiar with the details told USA TODAY Sports.

The person requested anonymity because he was not allowed to speak publicly until the trade is official.

Walker, who battled injuries with the Celtics, has two years and $73.6 million left on his contract. There was some frustration on Walker’s end after the Celtics tried to trade him at the beginning of last season. The Celtics free up some salary cap space but are now in the market for a point guard heading into the draft and free agency.

Walker averaged 19.3 points and 4.9 assists in 43 regular-season games and missed Boston’s final two first-round playoff games against Brooklyn with an injury.

For the Thunder, they continue to stockpile first-round picks in their rebuild. The Thunder now have 19 first-round picks, including three in the 2021 draft.

Oklahoma City acquired Horford just before the start of the 2020-21 season from Philadelphia for more assets, including a future first-round pick. He played in just 28 games for the Thunder and did not play in the final two months of the season. Horford spent three seasons with Celtics before signing with Philadelphia in free agency in 2019.