CHAPEL HILL, N.C. (AP) – North Carolina freshman Marvin Williams signed with an agent Friday as expected, meaning the 6-foot-9 forward is definitely headed to the NBA draft. When he announced two weeks ago that he was entering the draft — along with teammates Rashad McCants, Sean May and Raymond Felton — Williams seemed sure he wouldn’t change his mind. His decision Friday to hire Jim Tanner of Williams & Connolly assured it. The company also handles stars Tim Duncan, Grant Hill and Ray Allen. Marvin Williams averaged 11.3 points and 6.6 rebounds in his only season in Chapel Hill. Despite not starting a game, he was named Atlantic Coast Conference Rookie of the Year and is expected to be among the first five picked in the NBA draft.