Which comes first: having a quarterback who’s worth protecting, or securing the pieces of an offensive line that can protect a quarterback?

Most would say the former, and it wouldn’t be close. In an increasingly quarterback-driven league, good is merely adequate at that position.

But what if you’re a general manager and your quarterback recently suffered a significant injury, leaving a lingering question mark heading into this season? And what if although you’re confident he can come back and do so strongly, you need to see him run, scramble, and get hit for a full season prior to making a decision on his future with your team?

That’s where Texans general manager Rick Smith is with Matt Schaub, whose contract expires next March. And that’s why he prioritized Schaub’s primary protector as he was digging into his money sack.

Duane Brown guards Schaub’s blindside. You know, the side in which he can’t see angry defenders who want to hurt him when they’re running with arms flailing wildly. He’s also quite good at not breaking bones or ripping apart muscles, as he’s played in all but four games since being drafted with the 26th overall pick in 2008, and in every game he’s been a starter.

So you’re beginning to see why the Texans were eager to lock up the guy who’s entering the final season of his rookie contract, and is tasked with protecting their quarterback who suffered a Lisfranc injury last year. Oh, Brown was also rated the second best left tackle by Pro Football Focus in 2011, and the sixth-best offensive tackle overall. He’s worthy of a six-year deal valued at $53.4 million, no?

That’s what Smith gave Brown today, a contract that made NFL history as the largest exchange of money between the two most generic-sounding names. It contains $22.08 million in guaranteed money, and will pay Brown an average of $8.9 million annually. That’s catching up to but still under Cleveland’s Joe Thomas, the league’s highest-paid tackle who signed a deal worth $84 million last summer, and over eight years it’s worth $11.5 million annually.

For the Texans, the move contains more significance beyond just signing their best offensive lineman, which is pretty damn significant. Securing Brown became an even greater priority when Eric Winston and Mike Brisiel were allowed to walk as free agents. Letting a second-team All Pro left tackle leave next March would have been crippling, which is why a source told Pro Football Weekly that Smith wouldn’t use the franchise tag on anyone until Brown was signed.

Knowing that, without this deal the Texans could have lost an equally important defensive player. Connor Barwin had 11.5 sacks last year, and he’ll be a great bargain in 2012 at $565,000 in the final year of his contract. With Mario Williams now settled in Buffalo, Barwin is vital to Wade Phillips’ pass rush, and losing him could quickly derail a defense that made a swift turnaround during Phillips’ first season as Houston’s defensive coordinator. Now Barwin can be franchised if a deal isn’t reached.

Where does this leave Schaub? If a healthy Schaub has a healthy Andre Johnson all year, he’ll likely revert to his 2010 form when he had 4,370 passing yards, and finished with 24 touchdowns and 12 interceptions, a solid ratio even if his TD total wasn’t exactly spectacular. Conversely, a more typical Schaub who lacks durability (he’s missed 16 games since 2007) will limp around at some point, and get franchised as Smith continues to walk the safe walk with his 31-year-old quarterback.

So hey Matt, if you want to get paid, just don’t break anything. Simple.