The Baltimore Ravens have signed first-year center/guard Bryan Mattison off the practice squad, Aaron Wilson of the Carroll County Times reports.

Veteran offensive tackle Scott Kooistra has been placed on waivers.

Mattison (6-3, 313) is a converted defensive end who has spent much of the last 2 1/2 seasons on the Ravens' practice squad. With right guard Chris Chester expected to miss tomorrow's game against the Carolina Panthers due to a skin infection, Mattison adds depth at center and both guard spots.