Rivals: 3 star DE
Scout: 3 star DE

Mattison was a stalwart on the Defensive Line while at Iowa, but went undrafted entering into the NFL. He went to camp with the Baltimore Ravens but was cut before the season and joined their practice squad. It was there that he was converted into an Offensive Lineman. He remained on the Practice Squad listed as a Guard throughout the 2009 season, never seeing any game action during the regular season. He again tried to make the 53 man roster with the Ravens but was cut before the 2010 season began, signing on to the practice squad for Baltimore once again. He was activated to the roster on November 20th but was released a month later and signed to the practice squad. However in the Divisional Round of the playoffs, Mattison was moved back to the team’s roster, only to be listed as inactive. Mattison made the Ravens’ roster heading into the 2011 season as a backup Center. He was cut at the end of November and signed by the St. Louis Rams.