"I think he's done well," Harbaugh said prior to Saturday's practice at the team's training facility in Owings Mills. "He's playing center for the first time ever in his life. The things that happened with Bryan, I'm a little surprised at how well he's done blocking people. He's done a good job blocking both run game and pass game. I'm not surprised at the fact that we've had some late snaps, some early snaps and some missed call protections. So that shouldn't be surprising at all. I think he's done better than we anticipated, but those things are going to come up with a guy who really hasn't played the position."Mattison is a converted defensive end who was signed to the club's practice squad in 2009. Mattison, whose father Greg vacated the Ravens defensive coordinator position for the same role at the University of Michigan in January, has demonstrated his commitment to the organization with his acceptance to switch positions and excel on the offensive line, Harbaugh said.