There's a 50-50 chance we'll learn once again not to doubt running back Adrian Peterson's ability to recover quickly from injuries that appear too grim to overcome.

Peterson, who missed nearly three quarters of last week's game in Baltimore because of what appeared to be a serious sprain to his right foot, impressed coach Leslie Frazier enough during Friday's practice to be listed as questionable for Sunday's game against the Eagles at Mall of America Field.

Also listed as questionable were running back Toby Gerhart (hamstring) and cornerback Chris Cook (knee), who appeared on this week's injury report for the first time on Friday. Cornerback Xavier Rhodes (ankle) and right guard Brandon Fusco (knee) didn't practice and were listed as doubtful. Tight end John Carlson (concussion) was listed as out because he has yet to pass the NFL concussion protocol.

After two days of pool workouts, Peterson practiced for the first time this week Friday. According to Frazier, Peterson planted, ran and showed good burst with his right foot.

"It was impressive when you consider the early diagnosis," Frazier said. "He's unique. Very unique. He's so different than everybody else when it comes to recovering from injuries.

''We've been in situations in the past where you thought he wouldn't make it and he made it. So it was always in the back of my mind the chance he would make it."

Frazier sounded extremely optimistic, but was not willing to go beyond listing Peterson as questionable in part because he'll need to see how Peterson's foot responds Saturday after going through Friday's workout. Frazier also indicated a decision could come down to game time.

Peterson said the foot isn't fully healed, but added there's no concern about further damage and considers it just a matter of pain tolerance.

"I feel pretty confident [I'll play]," Peterson said. "I'm excited. … There's pain there, but there comes a point where you got to suck some of the pain up. I feel like with me trying to put pressure on it, the pain that I do feel I'm able to take that. But it's a different force when you're out there running and you're really planting and really being explosive."

Frazier said Peterson will have input on the decision, but added, "we have a medical staff for a reason." Frazier ultimately has the final say.

Why not shut it down?

Peterson was asked if he considered just shut shutting down his season with the Vikings mathematically eliminated.

"No, not at all," he said. "That's just not my mentality. To leave these guys out to dry just because of, what the heck? My passion for the game, I love the game too much to just sit out just because. If I'm out, it's going to be because you're going to know that, hey, he can't go."

Gerhart doesn't burst

Gerhart also practiced Friday for the first time all week. But he held back some to protect the hamstring until game day.

"We really didn't burst with him," Frazier said. "But everything he did stride-wise was good. He did a good job cutting and did all the things you'd want to see except for the burst."

Secondary issues

Barring the unforeseen, Marcus Sherels will start in place of Rhodes at left cornerback Sunday. Cook's injury was unknown to reporters when Frazier spoke to the media Friday, but during that interview, Frazier indicated that safety and current nickel back Robert Blanton would be a candidate to play on the outside.

"When you're getting as thin as we are, everybody is a candidate to be moving around and playing chess with," Frazier said. "You don't rule anything out at this point."

Smith close to returning

Barring an unlikely setback Saturday, free safety Harrison Smith will be activated from injured reserve and have a role in Sunday's game. Smith has been out the past eight weeks because of a turf toe injury. He returned to practice two weeks ago.

"He's practiced pretty well," Frazier said. "So far, so good."

Etc.

• Ravens linebacker Courtney Upshaw was fined $15,750 for his roughing-the-passer call late in the third quarter against the Vikings last week.