Run defense faces biggest test vs. Texans

Arian Foster has 10 rushing touchdowns and 770 yards on the ground, good for fifth in the NFL. Bob Levey/Getty Images

LAKE FOREST, Ill. -- Just how tough has it been to run the ball against the Chicago Bears? Over the course of their first eight games the Bears' sixth-ranked rushing defense (88.0 yards per game) has allowed only four rushes of 20 or more yards, and a single run of 28 or more yards -- Chris Johnson's meaningless 80-yard touchdown in the fourth quarter of the Bears' blowout victory in Tennessee.

Sunday night promises to be the Bears' toughest challenge to date stopping the run. Not only is Houston Texans tailback Arian Foster the NFL's fifth-leading rusher (770 yards and 10 touchdowns), but the Bears will have to contend with the Texans' zone blocking scheme that coach Gary Kubiak brought to Houston from Denver where he coached with Mike Shanahan and legendary offensive line coach Alex Gibbs.

"It's really a heck of a scheme, it really is," Bears defensive coordinator Rod Marinelli said. "Those guys, they execute and they come off the ball up front as well as any offense you will see in the league. It's a zone team and they stay on tracks. They do a fabulous job with the boots and the play action off of it. They sell the run and they've got play action and boots off of it. So it's tough, and we have to be on top of our keys and can't guess. We have to play fast and tackle well."

The signature play of Houston's run game is the wide zone where blockers try to push defenders outside toward the sideline while their backside offensive linemen throw cut blocks to slow down backside pursuit. Because the Texans' offensive line moves in unison at the beginning of ever play, it can be difficult for a defense to properly read its keys and determine run or pass.

Foster is such an ideal fit for this system because he can correctly read his blockers and hit the holes at full speed.

"He's a smart back, patient," Bears linebacker Lance Briggs said. "He understands their running game, their running style. It fits him well. He knows when to make the right cuts. He gets upfield and gets a lot of positive yardage. He's been doing it for a while. He's been one of the top backs and he's that way for a reason.

"When you look at a lot of the old Denver Broncos, when they were running the ball like crazy, it's a lot like that. A lot like that.”

Like the Bears, the Texans have a solid one-two punch in the backfield with Foster and second-string running back Ben Tate, who is averaging 4.1 yards per carry on 43 attempts. But Tate was inactive in Houston's last game and did not practice Wednesday or Thursday this week due to a hamstring injury.