NORMAN, OK – NOVEMBER 25: Quarterback Baker Mayfield #6 of the Oklahoma Sooners gestures to the crowd after Senior Day announcements before the game against the West Virginia Mountaineers at Gaylord Family Oklahoma Memorial Stadium on November 25, 2017 in Norman, Oklahoma. Oklahoma defeated West Virginia 59-31. (Photo by Brett Deering/Getty Images)Oklahoma Sooners players will be penalized for doing the “Horns Down” signal against Texas at the Big 12 Championship Game this afternoon.Baker Mayfield can do whatever he wants, though.The former star Oklahoma quarterback posted a message for his rival ahead of this afternoon’s Big 12 Championship Game.The message: Horns Down.“Can’t penalize this….HORNS DOWN. Go get what’s yours tomorrow boys,” Mayfield wrote on Instagram.Oklahoma enters today’s game against Texas looking for revenge for a loss earlier in the season. The Longhorns handed the Sooners their only loss of the regular season back in October.Today’s Big 12 Championship Game is set to kick off in about three hours.Oklahoma, needing a win to stay in College Football Playoff contention, is set to kick off against Texas at 12 p.m. E.T. The game will be on ABC.