HOUSTON -- Linebacker Brian Cushing is out for the season with a torn left knee ligament, leaving the unbeaten Houston Texans without their top tackler and one of their emotional leaders.

Cushing was hurt in the second quarter of the Texans' 23-17 win over the New York Jets on a low block by guard Matt Slauson. Cushing walked off the field on his own, but didn't return.

Coach Gary Kubiak said Tuesday that Cushing has a torn anterior cruciate ligament and will need surgery in two to three weeks, after the swelling subsides. Cushing was leading Houston in tackles (38) before Monday night's game.

"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. We're all just disappointed for him. It's a tough day for him."

The Texans (5-0) play Green Bay (2-3) in Houston on Sunday night. The loss of Cushing is a foreboding sign for Houston, which ran into a rash of injuries to some of its top players in 2011, including Andre Johnson (hamstring), Matt Schaub (Lisfranc fracture) and outside linebacker Mario Williams (torn chest muscle).

In 2010, Houston lost middle linebacker DeMeco Ryans to a ruptured Achilles tendon, and the team spiraled to a 6-10 record.

"I do know that there are crises in this league, and every team has them," Kubiak said. "We've had our share here the last couple of years, and boy, if this is the first one (this year), it's a big one."

Last year, the Texans overcame the injuries, finished 10-6 and won their division, with third-string quarterback T.J. Yates running the offense. Kubiak thinks that experience may help them overcome the loss of Cushing now.

"I do know what this group is made of and I know what they're capable of," he said, "and we'll find a way to work through it and somebody else will come out of this and become a good player for us. I have a lot of confidence in that."

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

Dobbins played his first four NFL seasons with San Diego, including one season under Wade Phillips, now the Texans' defensive coordinator. He was traded to Miami during the 2010 draft, released after one season and signed by the Texans in August 2011. He played in 15 games last season and four this year, mostly on special teams.