BOSTON, Mass. (AP) – The Boston Celtics have exercised the fourth-year option on guard Rajon Rondo.

Terms of the deal, which covers the 2009-2010 season, were not disclosed Friday.

The 22-year-old Rondo is entering his third season with Boston. He averaged 10.6 points and 5.1 assists last season, when the Celtics’ won their 17th NBA Championship.

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