Vikings Looking for Safety Help w/ Williams Down

The Vikings are looking for help at safety now that free-agent pickup Madieu  Williams is out with a neck injury. Coach Brad Childress says Williams could be out for an extended period of time. Second-round draft pick Tyrell Johnson started in last Friday's preseason loss to Seattle, but has missed two days of practice this week with an abdominal strain. Johnson is expected to practice today in Mankato, where the Vikings have two sessions of drills on the schedule. Tomorrow is their final day of training camp, and they play preseason game number two Saturday in Baltimore.