NASHVILLE, Tenn. -- The Houston Texans knew entering this offseason that their offensive line was one of the worst in the NFL, and they made it a priority to address the unit -- replacing four starters -- to ensure they could protect the franchise quarterback who was coming off ACL surgery.

But for the second week in a row, the offensive line struggled to protect Deshaun Watson. In the Texans' 20-17 loss to the Tennessee Titans on Sunday, Watson was hit nine times and sacked four times.

Texans quarterback Deshaun Watson had to escape pressure often on Sunday against the Titans. Jim Brown/USA Today Sports

If the Texans cannot figure out how to better protect their young quarterback, it could be a huge problem for this team, which is trying to go from worst to first in the AFC South this season.

The Texans are down an offensive lineman after they had to put right tackle Seantrel Henderson on injured reserve last week with an ankle injury. Because he will be out for the season, the Texans moved second-year player Julie'n Davenport to the right side and have 2018 third-round draft pick Martinas Rankin at left tackle.

Last season, the Texans allowed 54 sacks, which was second worst in the NFL. And after the Texans traded starting left tackle Duane Brown at the end of October, Houston allowed 28 sacks. That tied the Cardinals and Bills for most in the NFL during that span, according to ESPN Stats & Information. Houston did sign Henderson and guards Zach Fulton and Senio Kelemete this offseason, but through two games, the unit still has struggled.

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"We tried to slam the edges and tried to do a lot of things. But [the protection] was tough," coach Bill O'Brien said. "It was tough, no doubt about it."

After the game, Watson was asked if he felt like he had enough time to throw.

"I guess so," he said. "I mean, I felt fine. I don't worry about the pressure. I just try to get the ball to the open guy, and if I get hit, I get hit."

But for Davenport, not only do the Texans need to better protect Watson, the offensive line can't repeat the mental mistakes made against the Titans. Davenport was called for two false starts and Kelemete was penalized for clipping in the second quarter, which negated a 25-yard completion to DeAndre Hopkins. Rankin also was called for a holding penalty.

"We've got to execute," Davenport said. "We've got to hone in on the little things, and we just can't let little things and little mistakes affect us. We've got to ... strive for protection.

"I don't even want anybody to get within a yard or two of my quarterback. To me, if he gets touched at all during the game, I don't care how much time he had, it's not enough. So we've got to be better."