The Ravens' traditionally stingy defense has regressed into a vulnerable outfit whose lack of prowess at stopping the run lately is upsetting defensive coordinator Dean Pees.

"It makes me sick," Pees said. "It makes me sick is the best way I can put it. It really does. It's up to me and it's up to our staff to get this thing corrected."

It's questionable, though, whether the Ravens' defense will take a step forward or continue to struggle against a formidable Texans offense after losing inside linebacker Ray Lewis, pictured, and cornerback Lardarius Webb to a torn right triceps and a torn left anterior cruciate ligament and lateral meniscus, respectively.

The Ravens are allowing 396.7 yards and 19.7 points per game, and no longer have their emotional leader in Lewis, or their top cover guy and arguably their top tackler pound for pound in Webb.

The Ravens have surrendered 427 rushing yards over the past two games, including a franchise record 227 rushing yards per contest in a 31-29 win over the Dallas Cowboys.

The defending AFC North champions rank 26th against the run, allowing 136.5 yards per contest.

Cowboys running backs DeMarco Murray and Felix Jones ran roughshod over the Ravens with Lewis in the lineup.

Although Lewis has struggled to shed blocks this season and his range has eroded at age 37, the two-time NFL Defensive Player of the Year does have 17 years of experience working in his favor.

Now, the Ravens will rely upon Jameel McClain, who was signed to a $10.5 million contract during the offseason, at Lewis' vacated inside linebacker spot with Dannell Ellerbe stepping in as the weak side inside linebacker.

McClain is a reliable player who missed tackles against the Cowboys. Ellerbe is athletic and a good blitzer, but isn't considered to be as stout against the run.

They'll both be tested by Texans star running back Arian Foster, one of the most dynamic all-purpose backs in the league. His patience and vision on the zone-stretch play is outstanding, but he's coming off a bad game against the Green Bay Packers where he was stuffed in the hole throughout the game other than two short touchdown runs.

As for the secondary, Cary Williams becomes the top cornerback and will be largely responsible for guarding Andre Johnson after allowing two touchdown passes to Dez Bryant a week ago.

Cornerback Jimmy Smith starts opposite Williams with Webb on injured reserve.

Both have to raise their level of play for the defense to improve.