"We've got to make major improvements there because we're moving the ball, but we're not scoring touchdowns," O'Brien said. "We're kicking too many field goals. ... That's not a sustainable way to win games in this league and we know that. So, we're going to work hard to get it better this week."
Quarterback Deshaun Watson, who completed 33-of-44 passes for 375 yards with a touchdown and an interception in Houston's Week 5 win over Dallas, blamed his own execution for the lack of red zone finishes.
"We've just got to execute. That's pretty much it," he said. "You can be simple. You can be creative. It doesn't really matter what you do, you've just got to execute the play. The plays are designed to get the ball in the end zone, and if everyone does their job and does it correctly and I make the right throw and make the right read, the ball should end up in the end zone."
The Texans' offense ranks third in the NFL with 423.4 yards a game, but has scored just 23 points a game. Houston has finished with a touchdown on just 8-of-22 red zone chances so far this season.
"I think it's a combination of a lot of things," O'Brien said. "It's not a time for us to sit here and list all the things. I think it starts with me. I've got to do a better job of teaching it, designing it, and then there are some things that we have to do a better job of executing."
Star receiver DeAndre Hopkins has three 100-yard receiving games this season and leads the NFL with 594 yards receiving, but he knows the Houston offense needs to finish drives with touchdowns.
"We've got to score in the red zone to put the game away, but we'll correct those mistakes," he said. "These last two weeks have been big. ... Just everyone just believing and being able to have that will and that determination to get the job done at the end."
RB Lamar Miller is expected to play this week after sitting out with a chest injury. Miller was active for Sunday night's game against the Cowboys but didn't play.
WR Hopkins caught 9-of-13 passes for 151 yards in the Texans' Week 5 win over Dallas.
QB Watson completed 33-of-44 passes for 375 yards with a touchdown and an interception in Houston's Week 5 win over Dallas. Watson also rushed for 40 yards on 10 carries.
CB Kayvon Webster left Sunday's game in the first quarter with a quadriceps injury and did not return. His status is expected to be updated in the middle of the week.