MANKATO, Minn. (AP) — Minnesota Vikings quarterback Tarvaris Jackson sprained the MCL in his left knee after getting tangled with a defensive lineman in practice on Saturday, according to a person with knowledge of the injury.

Jackson was hurt when defensive lineman LeTroy Guion fell at his feet and rolled over his leg during an 11-on-11 drill and is day-to-day, said the person, who requested anonymity because an official announcement had not been made.

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.