Rudolph threw for 281 yards with two touchdowns and two interceptions in his collegiate debut starting in place of Daxx Garman, and the Cowboys lost 49-28 at No. 6 Baylor for their fifth straight loss Saturday night.
Garman was in uniform and wearing a baseball cap on the sideline, though coach Mike Gundy gave no explanation for the switch that takes a year of eligibility from the quarterback who finished high school in South Carolina early and enrolled at Oklahoma State in time to go through spring practice.
''We did what we thought was best four our team,'' Gundy said, repeating that when asked if Rudolph wanted to play.
When questioned about why Garman was out, Gundy responded, again without elaborating, ''We don't ever talk about injuries or personnel issue.''
The Cowboys (5-6, 3-5 Big 12) have their longest losing streak since also losing five in a row during Gundy's first season as head coach in 2005, and the last time the Cowboys didn't go to a bowl game. They have to win at No. 23 Oklahoma in two weeks to get to their ninth consecutive bowl game.
Bryce Petty and playoff-contending Baylor (9-1, 6-1, No. 7 CFP) weren't tripped up by the Cowboys again.
After throwing touchdowns on Baylor's first two drives that took a minute combined, Petty ran 21 yards for the final score. The Bears avenged their only regular-season loss of a year ago, a game in which their quarterback inexplicably tripped at the 1 with a clear path to the end zone.
''Redemption,'' Petty said. ''To have it go down in that fashion and me be able to get in the open field again, I don't know if it takes away the trip. ... It makes my mind ease up a little bit.''
Baylor won its 15th consecutive home game, matching No. 2 Alabama for the longest in the nation, on a dreary and rainy night along the banks of the Brazos River. The Bears stayed in a three-way tie with No. 5 TCU and No. 12 Kansas State for the Big 12 lead with two games left.
A year ago, Baylor was No. 3 in the country and undefeated through nine games when Petty fell short of the end zone with the game still scoreless. The Bears then fumbled and the Cowboys drove 99 yards for its first score in a 49-17 thumping that took Baylor out of the national championship picture even though it still won its first Big 12 title.
Baylor led 42-14 Saturday when Devin Chafin scored on a 1-yard run with 14:21 left.
But Rudolph threw a 68-yard touchdown to James Washington, whose 38-yard grab on the next drive set up a 2-yard TD run by Rennie Childs. The Cowboys were driving again when Rudolph's pass was intercepted by Orion Stewart to set up Petty's TD run with 3 minutes left.
''Looks like he played OK. He made some mistakes. He had a couple of poor throws. Obviously, he made a mistake there at the end on the interception,'' Gundy said of Rudolph. ''I thought he handled himself well.''
Rudolph, who finished 13-of-25 passing, wasn't made available to talk to reporters after the game.
Chafin ran for 106 yards and three touchdowns, while Shock Linwood had 113 yards rushing with a score for Baylor. Corey Coleman extended his nation's best streak with a TD catch in his seventh consecutive game.
While rain fell for several hours before kickoff and during much of the game, there was a break in the weather at the start. The Bears took full advantage.
Petty completed 18 of 29 passes for 262 yards, 149 of those coming on the first two drives - the first lasting 36 seconds and the other 25 seconds. Petty hit Jay Lee in stride for a 65-ayrd TD on the second play of the game and Coleman made an over-the-shoulder grab for a 54-yard score.
''We felt like we had to get it while we could,'' Briles said. ''Be real aggressive while the ball was dry and try to get points on the board because we felt rain was coming.''