Appearing on Dash Radio with DJ Skee (who provides pregame entertainment for Vikings home games), Peterson said he plans to play Sunday against the Indianapolis Colts, adding that a week of practice following his return from a torn meniscus "showed me I'm ready to roll."
Peterson will be the starting running back Sunday, the Vikings announced.
The Vikings officially activated Peterson on Saturday, who had surgery on his torn right meniscus Sept. 22 and has been on injured reserve since.
Peterson said Friday afternoon that he made the decision to play after talking with coach Mike Zimmer, running backs coach Kevin Stefanski and the Vikings' athletic training staff.
"I was able to come to the conclusion, talking to the head coach, my position coach and the training staff, that I'm going to go," Peterson said.
The betting line for Sunday's game has gone from Minnesota minus-4 to minus-5 at many Las Vegas sportsbooks since Peterson's announcement.
On Thursday, Zimmer had said that the call would come after a group discussion, adding, "It's a lot to do with the medical [diagnosis]."
Peterson said Thursday that he would wear a knee brace if he did return this season, which he typically has preferred not to do. Given how quickly he plans to return from the injury, though, the running back said it makes sense to take extra caution.
The 31-year-old running back opted in September for a full repair of his meniscus, which typically requires between four and six months of recovery. League sources told ESPN in November, however, that Peterson's knee was 90 percent healed and said the running back was looking to come back Dec. 18 against the Colts or Dec. 24 against the Green Bay Packers. Peterson said last week that it would be "pointless" to return if the Vikings -- who were 6-6 at the time before a win Sunday in Jacksonville -- were out of the playoff race.
He will have to reacquaint himself with an offense that has changed since Pat Shurmur replaced Norv Turner as offensive coordinator in November.
"There certainly are some new things we're doing that he's not as familiar with," Shurmur said. "He's been in meetings. He's been around. He's somewhat familiar with what we're doing. But knowing it and actually executing it are two different things."
Said Peterson on the radio: "I've been having my head in the playbook this week, just anticipating going out there as well. I've got some things I need to clean up a little bit, but I'll be out there on Sunday."
According to a Billboard story from August 2014, Peterson was one of the founding investors in Dash Radio, a free streaming music service founded by DJ Skee, aka Scott Kearney, a Twin Cities native.