With the loss of Paul Kruger to the Cleveland Browns already this off season it makes sense that the Baltimore Ravens would be looking to replace him with another pass rushing threat to work opposite Terrell Suggs.
The first name to be brought up in regards to the Ravens was ex Pittsburgh Steeler James Harrison, who is at the tail end of his career but could definitely still provide some pass pressure on third downs. Harrison is no longer a three down player but could easily fill the void left by Kruger.
However the talks between Harrison and the Ravens have cooled down of late as the Ravens look to be zeroing in on new free agent Elvis Dumervil formerly of the Denver Broncos. Dumervil is now the top free agent pass rusher on the market and Baltimore has a bit of cap space to work with if they want to try and sign him. It is said that at this point Dumervil and the Ravens are actually in contract negotiations. Most NFL media pundits have Elvis returning to Denver as the most probable option but Baltimore is a close second.
There is also ex-New York Giant Osi Umenyiora who could be available for less money than Dumervil but more money than Harrison, mostly due to age and production of late. Some say that Umenyiora wouldn't be the ideal fit for the Ravens defensive scheme but with a player with his versatility and athleticism, I'm sure the team would find ways to put him in a position to contribute heavily.
Indianapolis Colts cast off Dwight Freeney is also an intriguing option. you would have to think that if the Broncos do end up losing Dumervil to the Ravens or whoever Freeney may end up playing with his former quarterback Peyton Manning once more in Denver but if Dumervil decides to stay in Denver Freeney could wind up being the next player to start "negotiations" with Baltimore.
Of all the players mentioned above, by far, Dumervil has the highest ceiling. Not to mention Harrison, Freeney and Umenyiora are coming off mediocre season at best with their former teams, hence their release. It is true that a lot of players just need a new environment to return to their dominant form and many end up doing so when the come to Baltimore but if it was my money, I'd put it all on Elvis!