Minutes before a news conference with Ravens coach John Harbaugh and the recently re-signed Jameel McClain, Baltimore announced the identity of the mystery fourth free agent they locked up today.

The Ravens have signed veteran safety Sean Considine, who has played 83 career games in seven NFL seasons. In 2011, he spent time with both the Carolina Panthers and the Arizona Cardinals. He has also spent time with the Jacksonville Jaguars and the Philadelphia Eagles, who drafted him in the fourth round in 2005.

Considine has recorded 253 career tackles, 2.5 sacks, four interceptions and five forced fumbles. Brought in to bolster the special teams unit, Considine had 93 special teams tackles in his career.

Earlier today, the Ravens agreed to terms with former Chicago Bears defensive back Corey Graham and linebacker Brendon Ayanbadejo, who has been with the Ravens since 2008. Each was brought in with special teams in mind as their coverage team units allowed three return touchdowns in 2011.

“With Corey and Sean, we have improved our special teams, plus they give us quality and proven depth for the defense,” Ravens general manager Ozzie Newsome said in a statement. “When we ended the season, [coach] John [Harbaugh] and I talked about the need to get better players for special teams, especially with kick coverage. Corey and Sean will improve that area for us.”