Minnesota Vikings’ Adrian Peterson makes his way off an NFL football practice field at Winter Park in Eden Prairie, Minn., Friday, Oct. 11, 2013. Peterson said he is certain he will play Sunday despite a serious personal matter that caused him to miss practice earlier this week. (AP Photo/The Star Tribune, Elizabeth Flores) by Dave CampbellAP Pro Football Writer MINNEAPOLIS (AP) — When Adrian Peterson was 7, he saw his older brother die in a bike accident when he was hit by a drunken driver. For Peterson’s teenage years, his father was in prison. He grew up poor in east Texas. Shortly before the Minnesota Vikings drafted him in 2007, a half-brother, was shot and killed. Long before Peterson began running through the NFL record book, he learned to turn tragedy into fuel for an exceptional career. Football has always been his escape, and now he’s dealing with more off-the-field strife.