Peterson hasn't practiced all week after hurting his left ankle last week against Oakland. He was carted off the sideline Sunday and X-rays were negative. An MRI on Monday showed a Grade-1 high ankle sprain, the least severe of the three categories, and he had been in a walking boot for three days this week.
"With the limited amount of things he was able to do today, very, very doubtful he would make it, though," Minnesota coach Leslie Frazier said.
Peterson is sixth in the NFL in rushing with 872 yards. He's tied with Philadelphia's LeSean McCoy with a league-leading 12 touchdowns.
Peterson was out of his walking boot on Thursday and did some pool work. He tested the ankle again Friday but couldn't practice. He walked out to watch individual group drills at the Vikings' facilities before walking off the field with head trainer Eric Sugarman.
"The trouble he had was when he got up on his toes to plant or make a cut, that's where he had trouble," Frazier said. "So, that being the case it's doubtful he'll be able to get to the point where by Sunday we felt like he would be able to get out there. But we'll see. The fact that he can put pressure on that ankle, that's a positive sign.
"He's made progress, but being able to cut, as we all know, is a major part of what he does."
At 2-8, Minnesota has little incentive to rush its franchise back to return. Peterson signed a seven-year, $100 million contract extension during the preseason.
Toby Gerhart, the 2009 Heisman Trophy runner-up in his senior season at Stanford, would start in Peterson's absence. Frazier said Lorenzo Booker could also see some time at running back and receiver Percy Harvin will continue to receive limited carries.
Tight end Kyle Rudolph missed practice all week with a quadriceps contusion and is listed as doubtful.
Tight end Visanthe Shiancoe (hamstring) and receiver Percy Harvin (ribs) are listed as questionable after practicing on a limited basis Friday.