Just before Thursday's 3 p.m. ET trade deadline, the Boston Celtics agreed to ship center Kendrick Perkins and guard Nate Robinson to the Oklahoma City Thunder for swingman Jeff Green and big man Nenad Krstic, two league sources told ESPN.com's Chad Ford on Thursday.

Celtics director of basketball operations Danny Ainge said Wednesday that Perkins is out at least a week after spraining the medial collateral ligament in his left knee.