MANKATO, Minn. -- Minnesota Vikings quarterback Tarvaris Jackson suffered a sprained MCL after getting tangled with a teammate during a Saturday morning scrimmage, according to a report in the Minneapolis Star Tribune.
The Web site ProFootballTalk.com was the first to report the injury.
Jackson has had an MRI exam, according to the Star Tribune.
Jackson was injured when defensive lineman Letroy Guion fell at his feet and rolled over his leg during an 11-on-11 drill. Jackson folded to the field in pain as trainers rushed to check on him. After a few minutes, he was able to get up and walk off under his own power.
"I really don't know what happened," Guion said. "Everybody was moving so fast."
The fourth-year pro first received some attention at a tent on the side of the field before heading to the team's locker room area at Minnesota State University, Mankato.
Jackson did not return to practice and there was no immediate word on the nature of his injury.