Stillwater, Okla. ? Drafted by the New York Yankees in the second round, Brandon Weeden was a starting pitcher all the way.

After giving up baseball, the strong-armed right-hander earned perhaps his biggest victory as an ace reliever.

Weeden, the third-string quarterback for No. 12 Oklahoma State, threw for 168 yards and two touchdowns in the second half to lead the Cowboys back from an 11-point deficit for a 31-28 victory against Colorado on Thursday night.

“Right when we came out from halftime, I just kind of got a couple snaps, threw about five or six passes, and I was throwing fire,” Weeden said. “I like that. I really do. I think that’s fun.”

With starter Zac Robinson injured and backup Alex Cate ineffective, the Cowboys (9-2, 6-1 Big 12) turned to Weeden to spark the offense.

His 28-yard touchdown pass to Justin Blackmon with 8:11 remaining proved to be the winner, keeping pressure on No. 3 Texas in the Big 12 championship race. The Longhorns would have clinched the Big 12 South with an OSU loss.

“We kept on giving him the 1-ball, and he kept throwing the heater, and finally we made a catch or two — and he made some plays with his feet, too,” offensive coordinator Gunter Brewer said.

Colorado got out to a 21-10 lead against the one-dimensional Cowboys before Weeden finally provided a viable passing threat. He went 10-for-15 and threw a 47-yard touchdown pass to Keith Toston.

Weeden had to give up baseball when he started having problems with his pitching shoulder, and he can’t explain why it doesn’t affect him nearly as much when throwing a football.

The lessons the 26-year-old learned during five years in the minor leagues — never rising higher than Class-A — paid off in his first big chance on the college football stage.

“Not necessarily my age, but I think baseball really helped me out. Being 18 years old and basically you’re just thrown in the fire,” Weeden said. “Move halfway across the country and they said, ‘Here’s a baseball. Go throw it.’ Really and truly.”

The Buffaloes (3-8, 2-5) had one final chance to go for the win after stuffing OSU on fourth-and-short for the third time in the game with 3:14 remaining but decided to punt after Tyler Hansen threw three straight incomplete passes. The Cowboys, the Big 12’s top rushing team, ran the final 2:45 off the clock.

Oklahoma State wore black uniforms for the first time since 1994 — a miserable 3-7-1 season — and they didn’t seem to be a good luck charm in the team’s first Thursday night home game since 1995.

Cate, who had attempted only five passes in his career, started in Robinson’s place but went 0-for-9 with an interception in the first half — and it could have been worse. Colorado players had chances for at least two more picks, but let the ball slip through their hands.

Weeden came on in relief and connected on his first pass before throwing three straight incompletions for a three-and-out. When he completed back-to-back passes on OSU’s third drive of the third quarter, the crowd of 50,080 let out Bronx cheers.