Trade grades: Celtics send Kemba Walker, No. 16 pick to Thunder for Al Horford in blockbuster deal | CBS Sports Headlines Trade grades: Celtics send Kemba Walker, No. 16 pick to Thunder for Al Horford in blockbuster deal Walker is getting a change of scenery while Boston reunites with Horford … Continue reading Trade grades: Celtics send Kemba Walker, No. 16 pick to Thunder for Al Horford in blockbuster deal