The Minnesota Vikings and center John Sullivan have agreed on a five-year extension, Tom Pelissero of 1500ESPN.com reports. According to Pelissero, the extension is worth $25 million with $10 million guaranteed. A sixth-round pick out of Notre Dame in 2008, Sullivan sat behind Matt Birk for a season before assuming the starting job in 2009. Sullivan has started 42 games over the last three seasons and was scheduled to become an unrestricted free agent in 2012. Source: Mac's Football Blog
