Nose tackle Aubrayo Franklin left the 49ers' practice field on a cart Monday with a knee injury.
Franklin, who left Baltimore to sign with San Francisco in the offseason, was injured when two offensive linemen rolled onto his leg during a play. He fell facedown, then rolled over holding his left knee while trainers huddled around him.
Coach Mike Nolan said Franklin sprained his knee but will undergo more tests.
49ers' DT Franklin Leaves Practice Field With Knee Injury