Vikings sign QB Cassel

Not having a backup quarterback capable of winning a big game was a fatal flaw for the Minnesota Vikings in the 2012 playoffs.

They attempted to address the problem on Thursday, signing former Kansas City Chiefs and New England Patriots starter Matt Cassel just hours after he was officially released by Kansas City.

Cassel had 19 turnovers in nine games last season, but has 58 career starts. If he doesn't compete with 2011 first-round pick Christian Ponder for the starting job, Cassel would be considered an upgrade as the No. 2 quarterback.

Joe Webb, a converted college wide receiver, was forced to start the season-ending playoff loss at Green Bay when Ponder's elbow flared up.