The Vikings and Cassel came to agreement on Thursday, the same day he was formally released by the Kansas City Chiefs with two years left on his contract. The person spoke on condition of anonymity because the deal, first reported by Fox Sports, has not been announced.
Cassel spent the last four years in Kansas City. He completed 58 percent of his passes for 1,796 yards with six touchdowns and 12 interceptions in nine games last year.
Cassel will replace Joe Webb as Christian Ponder's backup. Ponder has been inconsistent his first two seasons, but GM Rick Spielman said when the season ended that Ponder is the starter for 2013.
