In the 2012 season, Adrian Peterson fell just short of Eric Dickerson's single-season rushing record. Dickerson set the mark with the Los Angeles Rams in 1984.
Peterson's 2012 campaign was remarkable because it came only months after major knee surgery. Playing for the Minnesota Vikings, he rushed for 2,097 yards and 12 touchdowns, earning the NFL's Most Valuable Player and Comeback Player of the Year awards.
Dickerson finished his record-setting 1984 season with 2,105 rushing yards. Peterson therefore missed the record by eight yards, although the question commonly describes the gap as nine. The achievement still ranks among the greatest seasons by an NFL running back.
Peterson's total was also the second-highest single-season rushing figure at the time. The performance helped Minnesota reach the playoffs and remains one of the strongest examples of an elite athlete returning quickly from a serious injury.