The Trinidad native went from undrafted free agent to a regular starter over the past five seasons with the Vikings, but his play has waned as he inches closer to his 32nd birthday. He was graded as the league's ninth-worst right guard by Pro Football Focus after the 2011 season, and the Vikings then made him a salary cap casualty. He met with Chicago Bears officials during the first couple of days of free agency, but he remains unsigned. Even with declining options, the Ravens should be able to do better at left guard than Herrera. But I couldn't resist including him when his addition could give the Ravens three former Vikings on their starting offensive line.