Five things learned about Texas' defense

AUSTIN, Texas -- To say the past month has been a crazy one for Texas' defense would probably be an understatement. Let's take a look back at what we know and what we still don't know after the first quarter of the Longhorns' season.

Here are five things we've learned about Texas' defense after four games:

1. Run defense problems resumed

Through four games, Texas is ranked last in the Big 12 in nearly every major defensive category. A lot of that has to do with the failings of its run defense, which currently ranks fourth-worst in the nation at 260.2 yards per game. While the BYU game did inflate those numbers, and the defense's performance against Kansas State helped, the stats are what they are. To some extent, they provide a glimpse into the uphill climb the Longhorns face in repairing their run defense, which has been battered by option football and mobile quarterbacks.

2. Bringing back Diaz was the wrong call

Not trying to beat a dead horse here, but we can't talk about the Texas defense's first four games without addressing the coordinator who coached in two of them. Mack Brown brought back Manny Diaz, believing he was still the right man to run the defense after a promising finish to 2012. Then BYU rushed for 550 yards, and a day later, Diaz was gone. Brown believed he couldn't afford to stick with Diaz and let this defense get any worse. If it took only two games to reach that conclusion, it's clear keeping Diaz this offseason was a regrettable move. We won't really know the full consequences of that decision until the end of the season.

3. With time, Robinson could get the job done

At this point, the aforementioned stats do not matter at all if Texas wins. That's all that's being asked of new defensive coordinator Greg Robinson at this point: He needs to put a defense on the field that can win games, that won't fall apart in key moments. Brown trusts that Robinson can coax his players into being better tacklers and playing with passion and consistent execution. He's still getting familiar with his personnel and implementing his own concepts, and we might not know what this defense can end up being for a few more weeks. Losing linebacker Jordan Hicks was a serious blow, one that will require making some key changes. But it seems Robinson's players have bought in and are serious about turning the season around.

4. Defensive ends, line emerge as strength

Texas knew it had an NFL-caliber talent at defensive end in Jackson Jeffcoat, but Cedric Reed has been a revelation. They two have combined for 52 tackles, eight tackles for loss and four sacks this season and have been one of the best aspects of this defense. The trio of Chris Whaley, Malcom Brown and Desmond Jackson has made strides, too, to form a front that can get after quarterbacks. If this defense gets where it wants to be, this line will be a big reason why.

5. Doesn't mean a thing until Oklahoma

The Longhorns could enjoy a breakthrough defensive performance against Iowa State and play one of their best games of Robinson's brief tenure. That wouldn't surprise anyone, even after the loss of Hicks. But just as the Red River game again will be the measuring stick for this season and this program, it also will serve as the real test of the Texas defense's progress. Brown hired Robinson to fix this defense in time for Big 12 play, and he needed to have serious progress by the time his team travels to Dallas. Against Oklahoma, he could cash in on his risky move and get big results, or Texas could pay dearly for it.