Chart: Adrian Peterson 2012 timeline

On Christmas Eve, 2011, Adrian Peterson planted his left leg during a run against the host Washington Redskins. He was hit by Washington safety DeJon Gomes and then helped off the field. Today, he is on the verge of setting an NFL record for most rushing yards in a season. Here is a timeline of the year's rehabilitation:

Dec. 30, 2011: Dr. James Andrews performs surgery on Peterson in Birmingham, Ala., to repair torn anterior cruciate and medial collateral ligaments in the left knee. Traditional timelines call for a nine-month recovery period, with at least a year before a player returns to 100 percent.

Jan. 2, 2012: Peterson begins rehab. "You think he's Adrian Peterson. Invincible. Doesn't bleed when you cut him," Vikings trainer Eric Sugarman says. "But for those two weeks? He was a disaster. Every morning, coming in and laying on that [trainer's] table and he was about as miserable as a human being could be. He was calling me late at night, texting me with hate messages. He didn't shave. He lost weight. He hurt."

Jan. 13: For the first time since his injury, Peterson walks without crutches. He said of watching the replay of his injury: "My stomach crawls just looking at it. Your leg is not supposed to go that way. At all."

March 26: With medical clearance, he begins running. Says Vikings coach Leslie Frazier: "He's a guy who wants to defy the odds with this injury. He wants to do things when he comes back that no one with an ACL tear has ever done."

May 9: Cleared to begin cutting on his knee, Peterson has an impressive 15-minute workout for reporters at Winter Park and vows to play in the season opener Sept. 9. "What I envision is to be suited up and ready to roll. Full strength," Peterson says. "Anything else? I would be cheating myself."

May 30: Peterson sprints up a hill at Winter Park, racing teammate Percy Harvin, during a team workout. "With the experts, I'm sure 90 or 95 percent of the time, they're right with their estimates," he says. "But there are some guys you can't put the traditional timetable on. Some guys are different. I just happen to feel I'm one of those guys."

July 27: Despite his protests, Peterson starts training camp at Mankato on the physically-unable-to-perform (PUP) list. During subsequent practices, he works out on the side of the field with trainers.

July 30: Peterson is rushed to a hospital and briefly hospitalized in Mankato after an allergic reaction during the team's lunch at training camp. "God has been testing me," he says.

Aug. 12: To his delight, Peterson is taken off the PUP list and begins practicing with his teammates.

Sept. 7: The Vikings say they have reached no decision on whether Peterson will play in the opener, which is three days away. "Oh yeah, I'm going to have a word in it. Believe that," Peterson says. "I will have my say."

Sept. 9: The Vikings open the season by beating Jacksonville 26-23. Peterson (shown above, before the game) rushes for 84 yards and scores two touchdowns.

Oct. 14: The Vikings return to Washington, and Peterson runs for 79 yards at the site of his devastating knee injury. It would be the last time to date he fails to run for 100 yards.

Oct. 21: Peterson runs for 153 yards in a victory over Arizona, beginning an eight-game tear where he rushes for 1,313 yards. It's the best eight-game rushing streak in NFL history.

Dec. 23: The Vikings play at Houston today, and Peterson has 1,812 yards. He is 293 yards away from the NFL record, set in 1984 by Eric Dickerson of the Los Angeles Rams.