Updated

Now, the Houston Texans really have some issues on defense. Luckily, they have a bye week to sort them out.

Already the league's worst at stopping the pass, the Texans lost All-Pro middle linebacker DeMeco Ryans to a season-ending injury in Sunday's 35-31 win over Kansas City. Houston was already missing Xavier Adibi (hamstring), Kevin Bentley (knee) and Darryl Sharpton (ankle), and was down to three healthy linebackers in the second half.

Coach Gary Kubiak said Monday that he hopes Adibi, Bentley or Sharpton can recover and learn Ryans' position in time for the Texans' next game, at Indianapolis on Nov. 1. Kubiak and general manager Rick Smith will also consider signing a free-agent linebacker or trade for one leading up to Tuesday's deadline.

"We have to look at everything," Kubiak said. "We have to look at any possible availability out there we think can make us better and help our team throughout the next 10 weeks. It's an ongoing process."

Ryans ruptured his left Achilles' tendon against the Chiefs and will have surgery this week. He had started 70 consecutive games and is the franchise's leader in solo tackles (435).

Zac Diles moved to Ryans' spot on Sunday, and David Nixon, a second-year linebacker from BYU moved into Diles' spot on the weak side. Brian Cushing handled the strong side in his second game back from a four-game suspension.

Kubiak said the trio was shaky without Ryans' leadership.

"I don't think we played well at the linebacker position," Kubiak said. "We didn't play well in the first half, and then when we lost DeMeco, we end up with Zac trying to run the defense and a new face (Nixon) trying to go on the field who hasn't been with us long. We just kind of got in disarray."

The Texans (4-2) still rallied from 10 points down in the fourth quarter to secure the best 6-game start in franchise history. The offense hasn't been a problem in Houston's victories, scoring at least 30 points in each.

But the defense could not generate a turnover and didn't have a sack until the final play against the Chiefs. Dwayne Bowe became the fifth player to reach 100 yards receiving against Houston, and Kansas City nearly had two 100-yard rushers.

The Texans rank last in pass defense (306 yards per game), second-to-last in scoring defense (27.8 points per game) and 21st in sacks (10) and interceptions (4).

"We need to get better across the board on the defensive side of the ball," Kubiak said. "Right now, we're in an evaluation process of ourselves, over the course of the next few days, trying to see what positives we can draw from what we've been doing and build off those.

"But when you're having mistakes, that usually brings you back to simplifying. That's something we're checking from a coaches' standpoint right now, and seeing if there's any changes we could possibly make that could make us better."

Kubiak said he saw progress on Sunday from second-year cornerback Glover Quin and maligned rookie cornerback Kareem Jackson, who's taken the brunt of the criticism for the Texans' problems in the secondary.

Kubiak added that he and Smith are not probing the market for veteran cornerbacks, reiterating that he's sticking with Quin and Jackson.

"We're going with those guys," Kubiak said. "Are we complete? We're not even close to complete, but that's the group we're going with. They've got to continue to improve."

Last season, the Texans' defense ranked as one of the league's worst through the first three games, then showed the most statistical improvement of any defense over the final 13 contests.

Kubiak can't figure out why this year's defense actually seems to have taken steps backward in recent weeks.

"That's the puzzling thing," Kubiak said. "We have the same guys, we're doing the same things, but we've regressed in some areas. That's what's really concerning right now. We're addressing it as coaches, we addressed it with the team.

"We've got to get them feeling good about what we're doing and why we're doing it," Kubiak said. "It's a problem we all have to solve, not one of us, or two of us."

Notes: LT Duane Brown rejoined the team Monday after serving a four-game suspension for violating the NFL's policy on banned substances. Kubiak said Brown will immediately take back his starting role after Rashad Butler replaced him during his absence.