The Vikings today signed linebacker Dontarrious Thomas, giving themselves much needed depth at the position. Thomas, we recall, played for the Vikes from 2004-2007, but left this off-season to sign a big free agent contract with San Francisco. Thomas failed to stick with the Niners however and two weeks ago the Vikes brought him in for a workout. The injury to David Herron yesterday, on top of E.J. Henderson being put on IR and his brother Erin suffering a concussion, put the Vikes in a bad position at linebacker. Thomas obviously has knowledge of the system and can be plugged right in at MLB.