Bill O'Brien has little tolerance for mental blunders. That much is already clear. Now the new Houston Texans coach just needs to make sure the franchise doesn't make one in Thursday night's NFL Draft.

While the draft looms over all, Case Keenum, Ryan Fitzpatrick and T.J. Yates are already taking their first practice field spins in O'Brien's complex new offense. It's an offense that Fitzpatrick calls "multiple" because it offers so many different looks and adapts based on each opponent's defense.

But just because it's intricate doesn't mean O'Brien is handing out free passes on mess ups. First full practice field day of voluntary mini camp or not.

"The attention to detail and just the expectations of perfection,"Fitzpatrick says after a Tuesday practice, "are a couple of things that really stuck out to me today."

The Harvard educated NFL journeyman notes that if something's gone over in the meeting room you're expected to pick it up and be able to apply it on the field immediately. O'Brien — who comes across as a much more hands-on practice coach than Gary Kubiak, one who's liable to jump right into a drill to correct something — is hardly an advocate of easing into things.

The pressure on Fitzpatrick, Keenum, Yates and whichever quarterback the Texans draft at some point will be intense. Every day's a measuring stick. No matter how much O'Brien down plays everything in his own media sessions.

"It was a decent start but we’ve had 'em for a little bit," O'Brien says, noting the team's pre-practice field work over the last several weeks. "I thought the ability to take it from phase one in the weight room to phase two in the coaching sessions and now to a practice . . . . We kind of built up to this.

"It was a typical first practice, but they handled things pretty well.”

Now, the Texans must handle the draft well — and not reach to force another quarterback into the quest for perfection mix. The only way the Texans should trade away the No. 1 pick is if a team offers a Herschel Walker or Ricky Williams type deal. And no NFL team's dumb enough to offer a Herschel Walker-sized trade these days.

You don't give Jadeveon Clowney — and Clowney is the only player in this draft worthy of a No. 1 overall pick — up for anything less than a crazy bounty. We're talking about the best defensive prospect in a generation. Jadeveon Clowney is worth more than the haul the Washington Redskins gave up for Robert Griffin III a few years ago.

No Clowney's not a quarterback. But he's the rare guaranteed game changer. Clowney can completely mess up an offense. He'll haunt quarterbacks like crack house pictures haunt AWOL Toronto mayor Rob Ford.

It'd be sacrilegious to compare any other prospect to Lawrence Taylor. With Clowney, it's a viable reference point.

You need to get a king's ransom to give up that kind of talent.

Texans owner Bob McNair (in another exclusive landed by Fox 26's Mark Berman) rightly calls Clowney clearly the best player in the draft. But McNair seems to miss the true scope of Clowney's supernova talent when he qualifies it by noting that the South Carolina star is not a quarterback.

Yes, the NFL seems like a more quarterback dominated league than ever. But which team won it all?

With Clowney, J.J. Watt, Brian Cushing and a few more smart additions, the Texans would suddenly have the closest thing to Pete Carroll's Seahawks defense that the AFC can offer.

Look at Russell Wilson's statistics and his playoff games. A slightly more seasoned Case Keenum could have won a title with Richard Sherman and Co. ball hawking as well. The Houston media doubters don't want to see that.

But all that matters is what Bill O'Brien believes. Tom Brady never would have been discovered in most rigid, unthinking NFL organizations. After spending some time with Bill Belichick in New England, you have to believe O'Brien is going to run an organization that thinks. One that isn't afraid to defy convention.

Texans QBs Enough

Keenum, Fitzpatrick and whichever quarterback is drafted all figure to get a real chance under O'Brien. It's hard to imagine this coach deciding starters based on loyalty, draft status or cap figure the way Kubiak too often did.

The safer bet is that O'Brien will be more like Pete Carroll, unafraid to do something like cutting a big-dollar free agent like Matt Flynn the moment he shows he's not up for the job. This type of thinking gives Case Keenum a legitimate opening to grab.

Anyone who thinks Fitzpatrick's $7.5 million contract guarantees him first dibs on the starting job hasn't been paying attention. In the first day of practice, Fitzpatrick seemed to have the best early command of the offense. The 31-year-old's talking about wanting to be something of a teacher for all the young players in this offense.

"I hope that everything I’ve experienced in the past that I’ve learned from I am able to pass it on to some of these younger guys," Fitzpatrick says, "because I do feel a little bit old in the locker room now.”

Fitzpatrick's certainly qualifies as a senior citizen on this young Texans team. Only Andre Johnson and punter Shane Lechler have more NFL experience than Fitzpatrick on the current roster. Fitzpatrick also might be the steadiest quarterback right now.

Still, reading too much into voluntary mini camp might be as foolish as reading too much into Fitzpatrick's Red Sox-worthy, bushy beard. When someone asks Fitzpatrick about The Beard (Rockets guard James Harden), he laughs and acknowledges he's beard inferior.

"(Harden's) is definitely more impressive than mine, but there's still time," Fitzpatrick cracks.

No other player can help the Texans immediately make up time as quickly as Clowney. He's a franchise shifter.

You don't mess up that kind of once in a generation talent to get a mere extra pick or two. A package for Clowney needs to be ridiculous.

Otherwise, you're still going backwards. No matter who's at quarterback.