The 35-year-old Williams is no stranger to the AFC North, having spent the last eight seasons with the Bengals, for whom he started all 118 games he played. Williams was originally drafted by the Eagles in the second round of the 2000 draft.
Last season was a mixed bag for the 6-foot-4, 345-lb. Williams, who started nine games before being placed on injured reserve on Dec. 12 with an ankle injury.
"Bobbie is a guy who has been in the league for a long time," head coach John Harbaugh said in a team-issued statement. "We've played against him, and we like his style of play and his demeanor as a person and as a player. We're excited to have him as a member of our team."
How Williams fits into the offensive line plans remains to be seen. The Ravens drafted two offensive linemen - Kelechi Osemele of Iowa State and Gino Gradkowski of Delaware - in April, and both were competing with holdover Jah Reid for the starting left guard spot, vacated by Ben Grubbs' departure via free agency.
Williams has limited experience at left guard, but could be part of that positional battle. If nothing else, he's a veteran presence to push Reid, Osemele and Gradkowski.
In other Ravens news, the team announced at a press event this morning that it had reached a long-term deal with Baltimore-based Under Armour to rename its Owings Mills practice facility, which will be re-branded as the Under Armour Performance Center. Financial terms of the 10-year deal were not released.
Under the arrangement, Under Armour and the Ravens will work together on a series of community-based initiatives.