LOS ANGELES: Minnesota Vikings running back Adrian Peterson said Wednesday (Thursday in Manila) he will undergo surgery on his injured knee this week as his team acknowledged he may be sidelined for the rest of the season. Peterson, 31, told ESPN he would go under the knife on Thursday to repair a torn meniscus in his right knee following last weekend’s win over the Green Bay Packers. “(I’m) doing it with faith and optimism,” Peterson told ESPN. ESPN reported that Peterson, the leading running back in the National Football League last season, had suffered what was known as a “bucket handle tear.” The typical recovery time for the injury was between three and six months, ESPN reported. Vikings coach Mike Zimmer admitted on Wednesday that Peterson’s injury could be season-ending.