Although the Houston Texans are one of the NFL's two remaining unbeatens, there's suddenly a feeling of concern for Gary Kubiak's team.

Their problem, however, doesn't appear as troubling as what the Green Bay Packers are experiencing.

Following a season-ending injury to All-Pro linebacker Brian Cushing, the Texans look to regroup Sunday night when they host a Packers team coming off yet another discouraging performance in a stunning defeat.

Houston (5-0) is off to the best start in franchise history and has already begun to separate itself from the pack in the AFC South. Its path to the playoffs, however, took a major hit in Monday night's 23-17 win over the New York Jets, as Cushing suffered a torn left knee ligament on a low block by guard Matt Slauson.

"A big blow for our team," Kubiak said. "We have to have guys pick it up around him and we've got to find a way to move forward."

Cushing has a team-high 29 tackles and has led the Texas in that department in two of three seasons since being named the Defensive Rookie of the Year in 2009. He is also the emotional leader on a defense that ranks third in total yards allowed with 275.6 per game and fourth in scoring at 14.6 points.

Kubiak says Tim Dobbins, who moved into Cushing's spot Monday and finished with four tackles and a pass deflection, is "option No. 1" to replace Cushing in the lineup.

"It's a challenge for our team, that's what this is," Kubiak said. "We know Dobbins is going to go in there and play well, and every player in our locker room is going to take on a little bit more responsibility."

J.J. Watt is one player who is expected to help shoulder the load. He has eight pass deflections and 7 1/2 sacks, one-half less than league leader Clay Matthews of Green Bay.

Matthews, who played with Cushing at Southern California, came to the defense of his former teammate by calling out the NFL via Twitter for not protecting defensive players the same as it does for those on offense.

The Packers (2-3) also have plenty of injuries to overcome, one of several problems they face as they sit two games back of Chicago and Minnesota in the NFC North.

Green Bay seemed poised to move over .500 last Sunday, leading Indianapolis 21-3 at halftime. The offense then stalled, the defense couldn't stop the Colts and the usually reliable Mason Crosby missed a 51-yard field goal with 3 seconds to play in a 30-27 loss. It was the first time the Packers blew an 18-point halftime lead since 1957.

"We've got to win the next one. We've put ourselves in a hole," safety Charles Woodson said. "The only thing you can hang your hat on is that it's still early in the season and you've got a long way to go."

Running back Cedric Benson (sprained foot) was placed on injured reserve Wednesday, while tight end Jermichael Finley (shoulder) and defensive tackle B.J. Raji (sprained ankle) "have a chance" to play, according to coach Mike McCarthy. The status of Pro Bowl wide receiver Greg Jennings (groin) is uncertain.

While the injuries haven't helped Green Bay's situation, its offense is still not clicking like most expected.

After averaging 35.0 points last season, the fifth-highest total in NFL history, the Packers are averaging 22.4. Aaron Rodgers, who set a single-season record with a 122.5 quarterback rating in 2011, has already thrown four interceptions after being picked off six times in 502 attempts a year ago.

Benson, coming off three straight 1,000-yard seasons with Cincinnati, has been ineffective, averaging 49.6 yards. He must sit out eight games before he can return, and McCarthy says the Packers are "optimistic" Benson will be able to play in the last four weeks of the season.

"We're a focused football team; we're just not playing to the level that we want to play at right now," McCarthy said. "That's what we have to stay focused on. We have to stay focused on our habits, our discipline, our preparation, the process leading up to Sunday night."

Green Bay, which has allowed 57 points and 938 yards in its last two games, will likely have its hands full facing a balanced Houston offense.

Arian Foster is second in the league with 532 rushing yards, and by netting 168 total yards Monday, he amassed 5,000 scrimmage yards in his 40th NFL game, the third-fastest in league history.

Andre Johnson has caught just 17 passes for 283 yards, and with defenses focusing on stopping the five-time Pro Bowl receiver, Owen Daniels has often been left open for Matt Schaub. Daniels is third among tight ends with 311 receiving yards and leads the Texans with three touchdown receptions.

Schaub threw for 414 yards, the third-highest total of his career, as Houston won 24-21 in Green Bay on Dec. 7, 2008, in the last meeting between these teams.