"It's harder to say with him being in that boot, until we can actually see him move around and see how he is doing," Frazier said. "We'll have better indication once he gets out of the boot and starts moving around and putting some weight on it."
Peterson sustained the high ankle sprain Sunday against Oakland. Frazier said a combination of Toby Gerhard and Lorenzo Booker would be used in place of Peterson.
"When (Gerhart) had to play a year ago against the Redskins, he showed he's more than capable and this could possibly be one of those moments where he'll get extended reps as well," Frazier said. "We have confidence in him, it's just he plays behind the best running back in the National Football League but we know he's more than capable of doing a good job as a running back for us."
Left guard Anthony Herrera, who has missed the last three games with a knee injury, took part in a limited portion of practice on Wednesday. Frazier says the club will monitor Herrera throughout the week. Tight ends Visanthe Shiancoe (hamstring) and Kyle Rudolph (quadriceps) and safety Husain Abdullah (concussion) did not practice.
The Associated Press contributed to this report.