Jefferson took a hit to the head from teammate Jamarca Sanford as the two of them and Erin Henderson were trying to tackle Chicago Bears RB Matt Forte.
Jefferson laid motionless on the field for a few seconds, but he said he wasn't unconscious.
"Actually, I wasn't out cold. It was crazy. I've never had a concussion before so that experience for me was … I was actually conscious. I was kind of unresponsive for a little bit," Jefferson said Friday, two days after being clear of his concussion by an independent neurologist. "I was kind of dizzy and didn't know what was going on. I couldn't talk or respond for a little bit. Everything came back slowly. As soon as I came to, I felt fine. Of course, they have to take you in and test you."
Jefferson didn't return to the game, but his mother was in the locker room before the game had ended with concern that quickly turned to relief.
"My mom came down right in the middle of the game and she was in the locker room. She was fine until she saw that was OK and she actually started balling her eyes out," Jefferson said. "I was like, ‘You can't cry now. I'm fine now.' I guess it was a cry of relief for her."
Jefferson passed his final post-concussion test on Wednesday and began practicing on a limited bases Thursday. He was also limited Friday, but the Vikings listed him as probable on the injury report, meaning he is a "virtual certainty" to be available for Sunday's game against the St. Louis Rams.
He said it was the first concussion he's had and he didn't even experience any "major headaches" on Monday. That's quite the recovery considering how bad the incident initially appeared on Sunday.
"Yeah, it was crazy, man. I seen everybody talking to me and everything," he said. "You have that kind of experience and you're like, alright, you've got to take these head injuries seriously because that's not something I ever want to experience again."
The Vikings did list CB Antoine Winfield, the veteran starter of the team's secondary, as questionable on the injury report with a knee injury that has been bothering him more this week, but he is expected to play, according to head coach Leslie Frazier.
The Vikings will discuss whether to limit Winfield's snaps in Sunday's game. He didn't practice in the team portion Friday, according to the injury report.
The only other player to be limited in Friday's practice was RB Adrian Peterson, who was listed as probable for Sunday with an abdomen injury.
FAMILIAR WITH FISHER
Frazier and Rams head coach Jeff Fisher joined the Chicago Bears in 1981 and played together through the 1985 Super Bowl season.
"We were rookies together in '81. That was obviously a long time ago," Fisher said. "He was a great teammate. He was an undrafted free agent and made the club. We made the team together. We were there together for five years."
"… He's very smart, well-spoken, communicates well, understands big picture. He's very patient. I'm just really happy that he got an opportunity there and then obviously happy for his success so far this year."
BEST SINCE PAYTON?
Rams assistant head coach Dave McGinnis became the linebackers coach with the Chicago Bears in 1986, the year after Frazier's career essentially ended when he blew out his knee in the Super Bowl and the year after Fisher's professional playing career ended.
McGinnis has been coaching in the NFL ever since, and he went to the way-back machine when asked about Peterson.
"He's a special type of runner because he's strong enough to be able to power through when you stack a line against him, but at the same time he's got that God-given jump-cut ability where he sticks that foot in the ground and he can go," McGinnis said. "He's probably got the best stiff arm I've seen since Walter Payton. When he brings that thing out, it's a weapon. He's a very, very gifted runner. You can tell he's very passionate about it. Plus, those great runners, you can just tell by watching that they want the ball and he's all of that."
HIGH PRAISE AT 35
Winfield didn't practice this week, but the Vikings know how to preserve one of their best defensive players. Winfield's ability to talk earned high praise from Rams offensive coordinator Brian Schottenheimer.
"I think one of the most underrated players in the league – it's funny to say this for a 14-year veteran – but Antoine Winfield is still playing at an extremely high level," Schottenheimer said.
"… It's amazing. He's probably still, of all the guys we've played this year, the best supporting defensive back, corner in the league. He will come up and pop you. And so I think that whole secondary takes their lead from him and they're a very physical group."
Tim Yotter is the publisher of Viking Update. Follow Viking Update on Twitter and discuss this topic on our message boards. To become a subscriber to the Viking Update web site or magazine, click here.