The Vikings began listing Peterson on their injury report with an "abdomen" injury before their Week 15 game at the St. Louis Rams (he ran for 212 yards in that game). The 2012 NFL MVP, however, told ESPN's Josina Anderson in a telephone interview on Thursday that he suffered the injury in Week 11 against the Lions, "but I didn't know the extent I was hurt then."
"I just remember getting twisted up pretty bad in an awkward position. My jersey never moves like that. I don't know if it was from a tackle or from me pulling away from someone. I just remember thinking when I saw my jersey like that, that I must've gotten twisted up pretty bad. That next day I felt very uncomfortable in my groin and abdominal area. I thought to myself I'll just wait until I recover but I never did," he said.
Peterson finished the season with 2,097 yards, the second most in NFL history. He also participated in the Pro Bowl.
Peterson said the injury worsened each week and limited his participation in practice for the remainder of the season.
"With everything that I was going through with my knee, I just said to myself, 'I am not going to let this bring me down.' I just focused on doing my rehab, getting rest and continuing to play," he said.
He said the work he did in the offseason to return from surgery helped him to deal with the sports hernia injury.
"It was mind over matter. It was just about doing what I had to do to push myself every week. My body was sore from the game and the sports hernia every Monday, so I did what I had to do to recover and get my body right. I just played through the pain. I ran on adrenaline."
Peterson said he didn't receive any treatment for his pain until the Week 13 game against the Green Bay Packers, when he received a cortisone shot in the pelvic area.
He said the pain was the worst against the Houston Texans in Week 16, a game in which he finished with 86 yards.
"That was the first time that I really doubted myself and questioned whether I would be able to continue the season," he said. "The pain was a 10 on a scale of 10. Put it like this, I developed a new respect for Greg Jennings, who had the same type of injury. Initially I thought Greg was tripping and that he needed to be playing, but when I got it, I was like, 'I understand bro.' This is nothing to fool with," he said.
Peterson said the injury impacted his attempt to break Eric Dickerson's single-season rushing yards record, but he wouldn't use the injury as an excuse as to why he came up short.
"It definitely impacted my play. I wasn't 100 percent, but I wanted to win a championship. I wasn't going to stop or quit. I made a decision to keep going. I don't want to make it seem like the sports hernia made me miss it, I could have done it with the injury. All I can say is that I would have had better performances," he said.
The team said in a statement about Peterson's surgery that it expects "a speedy recovery" and that no long-term issues are expected.
Peterson told ESPN that he has been told he'll be able to work out again in three to four weeks.
ESPN reporter Josina Anderson and ESPN.com NFC North blogger Kevin Seifert contributed to this report.