The Ravens have agreed to a two-year, $7.5 million extension with Michael Pierce, a source told ESPN's Field Yates on Saturday, which keeps the starting nose tackle from becoming an unrestricted free agent at the end of the season.

Pierce, 31, has started all 16 games for a Ravens defense that has allowed the fewest points (16.4) and the fourth-fewest yards (302.1) in the NFL this season.