"We think we have two good players at those inside positions, but we did need to add some quality depth," Baltimore defensive coordinator Mike Nolan said. "Bernardo can really be an asset to us. He's very physical and has played in a similar scheme to what we're doing when he was in Green Bay."
The 6-foot-2, 250-pound Harris earned a Super Bowl ring with the Packers in 1996 and posted four consecutive seasons with 100 or more tackles.
Harris' best statistical season came in 2000 with a career-high 132 tackles along with 11 tackles for losses and two sacks.
An undrafted free agent from the University of North Carolina, Harris will likely be paid the veteran minimum salary of $750,000.
"You always look for veterans because they know so much," Hartwell said. "I'm looking forward to learning from Bernardo and having him around. He's a good football player."
Note: The Ravens waived linebacker Casey Tisdale and safety Chonn Lacey.