The Sooners are well aware of his improvements.
After managing just a 56.9 completion percentage in 2011, Ash has the nation's second-ranked completion rate in 2012 at 77.5 percent.
As indicative by that, Ash also ranks among the nation's tops in passing efficiency with a 180.06 rating, behind only fellow conference quarterbacks Geno Smith of West Virginia and J.W. Walsh of Oklahoma State.
Ash has thrown for 11 touchdowns to just one interception, while amassing nearly 1,300 yards--that already surpasses his entire total last year--and he's averaging 11.9 yards per completion and 9.2 yards per attempt.
"Those are pretty high percentages and pretty high numbers for touchdown passes without [many] interceptions," said OU defensive ends coach Bobby Jack Wright, whose group will be looking to put the heat on Ash Saturday. "And then on top of that, you take into the yardage that he's throwing for on top of the 200 that they're rushing for.
"So, he's a much, much better quarterback. He's more mature. He's more experienced."
Not surprising to Sooner head coach Bob Stoops.
"Yeah, just like you would expect," Stoops said. "With another year in the system, yeah I think not just Ash, but all of them feel more comfortable."
It's been most notable, however, with Ash.
He seems to have much better command of the offense and a stronger presence in the huddle this time around.
So much so that Stoops couldn't pinpoint just one area he's improved the most in.
"I [think] just overall, execution throwing the football and knowing where he wants to go with it and throws a good ball," Stoops said. "Accurate, so he does a good job."
Undoubtedly, the Longhorns' bread and butter is still the running game with tailbacks Malcolm Brown (he's still battling an ankle injury), Joe Bergeron and Johnathan Gray, but having a better and more confident signal caller poses a lot more problems for the Sooner defense.
Texas didn't really have that threat in store for the 2011 rout, which ended in a 55-17 Sooner dismantling at the Cotton Bowl.
Although he split snaps with Case McCoy, the then-true freshman Ash threw for a measly 107 yards and a touchdown on 11-of-20 passing in the game with a pair of picks.
He felt the wrath of a Sooner defense that raked in eight sacks on the day and 17 tackles for loss, led by now-NFL defensive end Frank Alexander's three sacks and four tackles for loss.
But they do, though, have that threat this time.
"He's a lot more mature," said OU strong safety Javon Harris. "It's something that we've noticed a lot, that I've noticed a lot just from watching film on Texas. You just gotta prepare for him. You know he can run. You know he's gotten a lot better at the passing game and especially these past two weeks. So we're just gonna go in here and game plan and just continue to do what we do and just continue to get better each week."
OU cornerback Demontre Hurst added onto that.
"Just seeing a few games from him, it's just the beginning of the season, just seeing him just out there more confident, just really out there just having more fun," Hurst said. "He's loose. He's feeding the receivers the ball and he's out there taking care of his business. O-line's taking care of him.
"You know, you could just see he's growing up. He's growing up. He's more mature, and he's really fitting their system and you can see the improvement in him."
An improvement that will force the Sooner defense into preparations for Ash's arm in this year's version of the Red River Rivalry.