SAN ANTONIO -- The Texas Longhorns have a lot to prove in tonight's Valero Alamo Bowl matchup against Oregon State.First, there's coach Mack Brown. For the past two seasons, Brown has been adamant that his program is moving in the right direction after a 5-7 record in 2010. He's pegged 2013 as a breakout season for the No. 23 Longhorns, who are 8-4 this season after an 8-5 campaign in 2011."I think in our process to move forward, we're about back to where we can compete at the highest level," Brown said Friday. "We'll have an older team for the first time since we made our changes next year, and I think we're making tremendous progress."Just how much progress Texas has made will become clear tonight against the No. 13 Beavers (9-3).Major Applewhite also has something to prove in his first game calling plays for the Texas offense. The former Longhorns quarterback was promoted from running backs coach when offensive coordinator Bryan Harsin was hired as head coach at Arkansas State earlier this month.Applewhite's challenge will be to find a way to get the ball in the hands of UT's numerous playmakers, something Harsin struggled to do consistently."I've always felt like, even as a player, this game is about players. Put it in the best guys' hands and let them make plays," Applewhite said. "I think sometimes we over-think it a little bit as coaches, so I'm excited to watch the guys go play."Quarterback David Ash needs to prove he is the right choice for Texas. Ash is 11-6 as a starter over two seasons but won't be guaranteed a starting job in 2013."I think David has made great progress, and [tonight] will be a big game for him," Brown said.Manny Diaz must prove that he is the right man to bring UT's defense back to its 2011 form, when it was the best unit in the Big 12 in his first year in Austin.The defensive coordinator flirted with the idea of taking the head coaching job at Florida International earlier this month, but he decided the situation was not ideal for him."It wasn't perfect, and I want to be at Texas," Diaz said. "I want to coach a great defense at Texas. And I know I can and I know that we will."But UT's defense has been anything but great this season. Texas is allowing 29 points and 413 yards per game. If UT gives up more than 258 yards against Oregon State, it will break the school record of 401.2 yards allowed per game, set in 1993."We know we've got to get this defense back on track from ... this year," cornerback Quandre Diggs said. "We're going to bounce back, I can promise you that."