The switch-hitting Williams, who hit .449 with 7 homers, 33 RBIs and 39 stolen bases this season for the Phoenix, signed with the Terps last Wednesday.
Brooks-DeBartolo was 13-9 in its second season of varsity baseball.
An Under Armour All-American last summer, the 6-foot, 185-pound Williams is ranked the 95th best senior in the nation by MaxPreps.
Williams will play second base and could hit leadoff for the Terrapins.
Reggie Williams Sr. said first-year Maryland coach Erik Bakich, a former assistant on some highly successful Vanderbilt teams, saw his son on the summer showcase circuit, including a Perfect Game showcase in Jupiter.
Other schools like Ole Miss, Miami, Oregon, UCF and USC showed interest in Williams, but the Terps showed the most.
"The coach came to the house while the team was down here," Reggie Williams, Sr. said. "That makes all the difference in the world. He told us he wanted him and wanted him to start. No one else was talking like that. He's going to get a chance to start in the ACC, so that's a rare opportunity."
Williams has also been selected to participate in the FACA All-Star Baseball Classic May 27-29 in Sebring, which is a top pro scouting event.
-- EDUARDO A. ENCINA (email@example.com)