The Boston Celtics have agreed to trade Kemba Walker, the No. 16 pick in the 2021 draft and a 2025 second rounder to the Oklahoma City Thunder for Al Horford, Moses Brown and a 2023 second round pick.

Horford left the Celtics to sign with the Philadelphia 76ers during the 2019 offseason. Horford has two years and $53.5 million left on his contract, with a partial guarantee of $14.5 million for 2022-23.

Walker is due $73 million over the next two seasons. With the Thunder in the middle of a rebuild, they plan on working with Walker as they previously did with Chris Paul, Carmelo Anthony and Horford.

The move marks the first for Brad Stevens since taking over the Boston front office.

Oklahoma City now owns three first round picks in the 2021 NBA draft.