NASHVILLE, Tenn. -- Protecting quarterback Marcus Mariota is always the top priority for the Tennessee Titans. As the franchise quarterback, he is their most important player.

Left tackle Taylor Lewan signed the largest contract in history for an NFL offensive lineman in part to serve as Mariota's personal protector. Over his career, Lewan has held his own against some of the top pass-rushers in the league such as Houston Texans All-Pro J.J. Watt.

Lewan suffered a concussion in Week 1, making his status uncertain for Sunday's home opener (1 p.m. ET, CBS) against the division rival. If he is unable to play, it will be bad news for a Titans offense that has to go against Houston's ferocious pass rush.

"He's [Taylor Lewan] a great player, man," Titans offensive coordinator Matt LaFleur said. "Any time you take a great player off the field it's a concern. But when one guy goes out, another guy has to be ready to step up. It's an opportunity for someone else to step up and execute the plan. You have to try as an offense to keep them as off balance as possible so you don't have guys flying off the edges."

The Texans have a stable of disruptive players who can get after the quarterback. Having served as outside linebackers coach and defensive coordinator in Houston, Titans coach Mike Vrabel is well aware of the threat posed by the Texans' defensive front.

"These guys are disruptive players, and it'll be important for us to have a good plan for them, and to block them and recognize where they're at," he said. "Watt is going to go wherever he wants, and [Texans defensive end/outside linebacker Jadeveon] Clowney is going to go wherever he wants, and [Texans outside linebacker] Whitney [Mercilus] is going to play with more technique and probably be in the right place most of the time."

Watt presents the biggest threat to the Titans. Injuries limited him to only eight games over the past two seasons, but he finished with three tackles and two hits on quarterback Tom Brady in the season opener against New England.

The Titans added offensive lineman David Quessenberry to the practice squad 10 days after he was released by Houston. Quessenberry spent five seasons with the Texans and practiced against Watt frequently, calling him one of the hardest workers he has ever seen.

"The play is never done with him," Quessenberry said. "He's always going, running down the field chasing balls. It's impressive to be around."

Few players have had an impact like Watt during his prime years with the Texans. He was the league's Defensive Player of the Year three times in four seasons (2012-15), amassing a whopping 69 sacks in that span before a herniated disk robbed him of most of the 2016 season and a tibial plateau fracture in his left leg cost him most of last season.

After starting his NFL coaching career with the Texans in 2014, Vrabel saw firsthand how Watt dominated.

"He's instinctive, he's big, he's athletic, he's long," Vrabel said. "He's a very athletic player for being as big as he is. I think that's the thing that's most impressive, is the size coupled with the athleticism. Normally a player that athletic isn't that big. He poses a lot of problems with the length and athleticism."

It's a given that Watt will see his share of double teams, especially if Lewan is ruled out this week. Left guard Quinton Spain is one of the players who will be asked to help out against Watt. Spain admires the way Houston's front hustles.

"Their effort to the ball stands out," he said. "They are nonstop. They work the edge and try to get to the quarterback. We have to protect."

Third-year Texans nose tackle D.J. Reader had two sacks against the Patriots last week. If he can consistently collapse the pocket from the inside, Houston's pass rush will become even more lethal.

"It's a good mix with him," Spain said. "He has the edge rushers, and all he wants to do is push the pocket, so if they get the edge rush he will be right there."

With or without Lewan in the lineup, the Titans have to find a way to neutralize Houston's relentless rush.