BALTIMORE -- The Orioles added right-handed pitching prospect Oliver Drake to their 40-man roster prior to Friday's deadline, thereby protecting him from next month's Rule 5 Draft. On Monday, the rounded out the roster by signing and adding free agent Matt Antonelli.

Drake, a United States Naval Academy product, went 11-8 with a 3.32 ERA at three different levels in 2011. The 24-year-old Drake threw two scoreless innings for the Norfolk Tides in the International League, and went 8-3 with a 2.14 ERA with the Carolina League's Frederick Keys before being promoted to Double-A Bowie, where he went 3-5 with a 5.20 ERA in his final 12 starts. In protecting just Drake, the Orioles left a few notables exposed to the Rule 5 Draft, including 2011 Minor League Pitcher of the Year Tim Bascom.

Any player who signed his first professional contract before age 19 and has been in an organization for five years, or who signed after age 19 and has been in the organization for four years, is eligible to be selected in the Rule 5 Draft if left unprotected.

The Rule 5 Draft takes place next month on the final day of baseball's annual Winter Meetings, and any player taken must remain on his new team's active roster or disabled list all season, or be offered back to his original club for $25,000.

The move left Baltimore's 40-man roster at 39, and though the Orioles were prohibited from adding another player from within the organization until the Rule 5 Draft is over, they did add Antonelli on Monday after the former first-rounder signed a Major League contract.

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 RBIs, 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."