The running back lacked the burst that typically defines his powerful, punishing running style as he managed just 65 yards rushing on the day.
"Actually, it was bothering me a lot," Peterson said of the injury. "There were a couple plays in the first half, oh man, I knew if I was able to explode the way I normally do I could have gotten some big chunks, even taken it to the house."
Peterson averaged just 3.1 yards on 21 carries against Seattle's formidable defense, his lowest per carry rate since Week 7.
"That groin is bothering him," coach Leslie Frazier said. "It definitely affected him. There were a couple of moments when he was so close to breaking it and just couldn't get that one key ingredient to get it going. He's not 100 percent."
Last season's NFL rushing leader brushed off the idea that he should sit out until the injury heals, saying "I'm going to try to get my rest that I need. I'm probably going to do it this week (in practice). Just push it to Sunday."
Peterson struggled through an almost identical situation earlier this season when he admitted a bruised hamstring was preventing him from exploding out of his cuts. He bounced back to average 4.7 yards per carry over his next three games.