1) Alex Okafor, defensive end
This is a pretty easy choice, if for no other reason than the fact that defensive coordinator Manny Diaz often says that Okafor is his most important player. Diaz has been known to state some variation of "for our defense to be great, Alex has to be great." And his sentiment is certainly correct. When Okafor is on, he's one of the best run-stopping AND pass-rushing defensive ends in the league. If he plays at a first-team All-American level — and he was probably there in the second half of last season — the defense has a chance to be great.
2) Adrian Phillips, safety
Look at the other secondary players. Carrington Byndom is probably the top cover cornerback in the league. Safety Kenny Vaccaro is in the discussion of the league's top safeties. Quandre Diggs was a freshman All-American last year. That leaves Phillips, whose versatility allowed him to be one of the team's top corners last year. Now, he'll be back at his more natural safety position, where his athleticism and ball skills could come in incredibly handy. If he plays up to his potential, Texas may have the best secondary in the country.
3) Steve Edmond, linebacker
With only one returning starter, it's imperative for Edmond to be all he's cracked up to be in the middle. Edmond had a huge spring and figures to be an excellent player in a defense that rewards players who can cause damage going forward. At 260 pounds, with his athleticism, Edmond certainly fits that bill. But he'll also need to be assignment sound in order for the Texas defense to reach its full potential.
4) Desmond Jackson, defensive tackle
Texas already has a deep and talented defensive tackle group. The only thing missing is one guy who commands double-teams and makes everyone else better. So why not Jackson, the stocky tank with a 500-pound bench press and great get-off? Ashton Dorsey could also be this guy, and led Longhorn defensive tackles with seven tackles for loss last year. But keep an eye on this emerging sophomore, as he has a chance to break out this year.
5) Demarco Cobbs, linebacker
Diaz said last year that the team missed out when Cobbs was injured, because of the way he can change games with his speed. And judging by the way the Longhorns are recruiting, Diaz would like one of his three linebackers to be more of a hybrid safety-type player with the athleticism to cover while also retaining a major blitzing presence. But Cobbs is also here because this spring it seemed that the drop-off from him to the backups was significant. It's vital not just that Cobbs does well, but that he stays healthy.