Minnesota Vikings running back Adrian Peterson will undergo knee surgery Thursday and will be out indefinitely.
Peterson, who was injured Sunday night, is "doing it with faith and optimism," ESPN's Josina Anderson reported.
According to Anderson, Peterson has a "bucket handle" tear, which usually requires three to four months of recovery and possibly six. Anderson, the Star Tribune and Larry Fitzgerald Sr., who is a Twin Cities sports reporter, all report that Peterson is having the meniscus repaired — which would lengthen recovery.
It is not yet clear what the Vikings will do with Peterson, who could be placed on the injured reserve list, designated to return after eight weeks.
This is not the same knee Peterson hurt during the 2011 season, when he tore the anterior cruciate ligament. He returned to rush for more than 2,000 yards in 2012, when he was named the NFL's Most Valuable Player.
Peterson was hurt after a 5-yard run in the third quarter against Green Bay. He jumped up after the tackle, but immediately grabbed his lower right leg, unable to put weight on it.