Injuries are starting to pile up for the Vikings.
Coach Mike Zimmer said Wednesday that defensive tackle Shamar Stephen and offensive tackle Carter Bykowski have had surgery.
Stephen had his knee scoped, but Zimmer said he will be back for the Sept. 14 regular-season opener at San Francisco. Bykowski had a procedure on his shoulder, and Zimmer said he doesn't know how long he will be out or whether it could be a season-ending injury.
The Vikings already have lost tackle for the season in Phil Loadholt, who tore his left Achilles tendon in last Saturday's 26-16 preseason win over Tampa Bay.