BOSTON, Mass. — The Boston Celtics exercised the fourth-year option on 22-year-old guard Rajon Rondo on Friday.

He averaged 10.6 points and 5.1 assists last season, when the Celtics' won their 17th NBA Championship. The former Kentucky Wildcat is entering his third season in the NBA.

The 6-foot-1 guard was acquired by Boston in a draft-night trade from the Phoenix Suns.