The Ravens signed Mattison last year and moved him to offense. Could be on the field next to Yanda, who was beginning to dominate at RG prior to tearing every living fiber in his right knee last year. (It was a McGahee-type virtual amputation.) Yanda is off the PUP and practicing. Once they moved Yanda inside, before the injury, what I noticed in games last year was that if he made contact, he had a startling physical advantage; he didn't push, he punched guys back on their heels. The only way to beat him was to make him miss.
Mattison's dad is now DC for the Ravens.