The Panthers have signed center Ryan Kalil to a six-year contract worth $49 million, according to team and league sources. The deal makes Kalil the highest-paid center in the league. Kalil was scheduled to make $10.1 million in 2011 as the team's designated franchise player and signed a five-year extension through 2016 that was restructured to lower his salary-cap number this year, according to the sources.