Vikings running back Adrian Peterson was downgraded to questionable for today's game against the Lions because he is battling an unspecified illness, the team announced Saturday.Peterson was initially listed as probable on the injury report with an injured finger.If Peterson is out or limited, Minnesota will turn to backup running backs Jerick McKinnon and Matt Asiata. Bucs activate Spence WASHINGTON — The Bucs activated defensive tackle Akeem Spence from the physically unable to perform list, and he'll make his season debut today against the Redskins.Spence, 23, missed the first five games after having back surgery in July. He had a career-high 37 tackles last season and adds depth behind starters Gerald McCoy and Clinton McDonald. To make room, the Bucs waived first-year offensive lineman Jeremiah Warren, who played at USF. Warren's cut suggests that Evan Smith, who had missed the past three games with an ankle injury, will be active today, perhaps as the backup center to Joe Hawley. QB INSURANCE FOR STEELERS: Pittsburgh promoted quarterback/receiver Tyler Murphy from the practice squad, likely meaning Ben Roethlisberger will miss today's game. Roethlisberger has not been officially ruled out, but third-stringer Landry Jones is the likely starter. Murphy, who played quarterback at Florida and Boston College, said he practiced at quarterback, receiver and special teams this week with Mike Vick out with a hamstring injury and Roethlisberger still recovering from an MCL sprain and bone bruise in his left knee. Murphy made the team to start the season before getting released Sept. 23 and signed to the practice squad the next day. COWBOYS: Dez Bryant has been ruled out for today's game, delaying the receiver's return from a broken right foot one more week. JETS: Punter Steve Weatherford has been brought back after the team announced that Ryan Quigley is questionable with an injured shin. Weatherford, 32, played for the team in 2009-10. PATRIOTS: Receiver Brandon LaFell has been added to the 53-man roster for today's game. He had been on the reserve/physically unable to perform list since Sept. 5 with a foot injury. Times staff writer Greg Auman contributed to this report.