Antonelli, 26, was the Padres' first round selection (17th overall) in the 2006 First Year Player Draft. He spent 2011 with Double-A Harrisburg (four games) and Triple-A Syracuse (86 games) in the Nationals' system, batting a combined .298/.390/.457 with eight home runs and 31 RBI, finishing in the Top-10 of the International League in on-base percentage. Antonelli is a career .264/.373/.406 hitter in 469 career minor league games over six seasons. He made his Major League debut in 2008 with San Diego, batting .193/.292/.281 in 21 games.
“We are pleased to bring Matt to the organization,” said Orioles Executive Vice President of Baseball Operations, DAN DUQUETTE. “He is a versatile major league player who has a good offensive approach and strong defensive skills at both third and second base.”
With this addition, the Orioles now have a full 40-man roster.