League sources told ESPN, The Athletic and the New York Post that Walker's representatives and Thunder general manager Sam Presti worked to come to an agreement on a buyout of the remaining two years and $74 million on Walker's deal.
After the buyout, Walker can now slide into the Knicks' roughly $10 million in available salary-cap space, ESPN reported.
The Thunder acquired Walker, the No. 16 overall pick in last week's NBA Draft and a 2025 second-round selection from the Boston Celtics in June. The Celtics received big men Al Horford and Moses Brown and a 2023 second-rounder in the trade.
Oklahoma City then turned that 16th pick into two future selections when the Houston Rockets acquired the draft choice to select Turkish center Alperen Sengun.
Walker averaged 19.3 points and 4.9 assists over 43 games for the Celtics this past season, his second in Boston. He averaged 20.4 points and 4.8 assists during the 2019-20 campaign with the Celtics.
Before joining the Celtics, Walker spent the first eight seasons of his NBA career with the Charlotte Hornets. He has averaged 19.9 points, 5.4 assists and 3.8 rebounds over 704 career games.