Can't challenge?

Referee Jeff Triplette just told the crowd the Cowboys cannot challenge the fumble, which seems confusing. We have requested a pool reporter to talk to the officials after the game for clarification. But I believe Wade Phillips was contending Felix Jones had the ball after Tony Romo was sacked and should have been ruled down by contact when it popped free. The Packers just made it 17-0 on Spencer Havner's touchdown grab. This game is over.