If season-ending injuries in the same game for Ray Lewis and Lardarius Webb weren’t a Ravens fan’s worst nightmare, seeing what the defense looked like without them on Sunday probably qualifies. Baltimore was blown off the field by the only other team (at the time) in the AFC with a winning record, the Houston Texans, in a 43-13 shellacking. The Texans did pick up nine points from a safety and a pick-six on a tipped Joe Flacco pass, but the Baltimore defense did still allow 34 points across 11 possessions, a 3.1-point average that was more than twice its 2011 points-per-possession average. Not good.

Most teams won’t have an offense quite as good as Houston’s, but I wanted to get a closer look at Baltimore’s defense post–Lewis and Webb to see how the Texans beat them. What will teams notice and reference for the future? Did the Texans really go after the Ravens’ replacements? And, most importantly, is this the “real” Ravens defense we’re going to be watching for the rest of the season?

Baltimore’s new starters each have some experience playing in the Ravens scheme, albeit not frequently as starters. 2011 first-rounder Jimmy Smith took over at cornerback for Webb, and he’d already seen plenty of snaps as the team’s nickel cornerback; at linebacker, longtime backup Dannell Ellerbe filled in for the irreplaceable Lewis. Ellerbe has started seven games over the previous three seasons, including three in support of an absent Lewis last season.

There’s a third injured player worth noting: Haloti Ngata. Baltimore’s star lineman has an MCL injury that he’s trying to play through, but it’s one that’s sapping his ability and availability. After playing 88 percent of Baltimore’s defensive snaps through the first five weeks of the year, Ngata’s been in the mid-60s each of the past two weeks, missing time during each of those contests with the knee complaint.

Ngata showed up on the first Texans touchdown, but it’s hard to avoid imagining that a healthy Ngata might have been able to prevent the touchdown. When you watch the play, you can see Ngata get penetration up the middle and beat left tackle Duane Brown to the inside, but quarterback Matt Schaub is able to easily sidestep him and make his throw. Ngata simply isn’t able to move horizontally with Schaub to extend the scramble and prevent him from looking back upfield.

When Schaub looks back up, he sees a pretty sight: Kevin Walter running a deep post two steps ahead of Cary Williams. The Texans run a flat/post combination with their two receivers to the left, and the Ravens simply don’t handle it very well. Bernard Pollard floats to the line of scrimmage to suggest man coverage, but the Ravens actually play zone after the snap, with Pollard around the line of scrimmage and Williams drifting back into a deeper zone. Walter sells like he’s running an out before cutting his post route back upfield, and even though the pressure delays the throw, Williams has no chance of catching up to Walter. It’s an easy score, truthfully.

Pollard and Williams combined to have a pretty awful game. Williams was already the team’s weakest starter on defense — and somebody who likely would have been replaced by Smith as the season went along if Webb stayed healthy — but the team is now stuck relying on him as their top cornerback. Pollard, who embodies all of the Ravens’ attitude without much of the sublime skill, took two incredibly stupid 15-yard penalties to extend and stretch drives. An unnecessary roughness penalty in the end zone on third-and-10 from the 22-yard line is bad enough, but Pollard also grabbed Owen Daniels’s face mask for a 15-yard penalty on a play that was on the sidelines and basically finished. Introducing new players to the defense is bad enough; the guys the Ravens were already starting need to step up and play more reliable football.

The Texans threw to Williams’s side of the field to pick up steady yardage, but when they needed a big play, they went after Smith. Walter was able to beat Smith twice with double moves, but both of Schaub’s throws were poor. The first one fell incomplete, and Walter had to slow down and fall to the ground to catch the second one. With better throws, Schaub would have had a three-touchdown day.

That completion to Walter works for a variety of reasons. For one, Walter doesn’t run a half-route on his fake. Ex-Bears safety Matt Bowen does great work breaking down film for the National Football Post, and one of his pet peeves is when defensive backs jump an out route that breaks eight yards past the line of scrimmage. Bowen commonly notes that every route in football will break between 12 and 15 yards, so there’s no need to honor the early cut, which is clearly setting up a double move. Here, Walter runs an out that’s 12 yards on the dot before accelerating and heading upfield. To let that route develop, you need to hold up in pass protection, and the six-man protection left Schaub and Walter a little over 2.5 seconds to let the route develop. Schaub has a clean pocket and throwing lane, which makes this pitch-and-catch.

Another reason it works is because Pollard, again the safety on that side, has to jump a dig route over the middle from the slot. The Texans seemed to beat the Ravens with an endless number of dig and drag routes over the middle of the field, specifically designed to take advantage of Baltimore’s inexperienced linebackers in coverage. The drag route from Daniels and Andre Johnson isn’t anything new for the Houston offense, but it was particularly effective by forcing players like Ellerbe and Paul Kruger to understand where they were in space while dealing with elite receivers. At its base, it created simple, easy throws for Schaub, and when Kruger dove for a ball that he had no prayer of deflecting, it turned an easy throw into a 12-yard completion.

Ellerbe had the best game of the new guys. The Texans certainly wanted to go after him, as they targeted him in coverage with throws to Arian Foster on each of the first two third downs they faced. That doesn’t mean that they threw a screen to Foster and Ellerbe had to make a tackle; they actually split Foster out at the line of scrimmage on the first third down and had him run a slant versus Ellerbe. On that play, Ellerbe was able to jar the ball loose after Foster’s catch; on the subsequent third down, Foster ran an option route and Ellerbe was able to get away with a slight tug on the star back’s jersey, forcing an incompletion. Houston mostly stayed away from that the rest of the way, and Ellerbe had a fine third-down tackle on a subsequent passing play that helped prevent a first down. On a day where the Ravens didn’t get to see many rays of hope, Ellerbe’s ability to hold up in coverage might have been one.

The offense can help the defense by sustaining their drives and creating better field position for the defense to work with. Under John Harbaugh, the Ravens’ defense has enjoyed very good average starting field position, but their average starting line of scrimmage (LOS) fell from third best in the league in 2010 to 20th last year and 22nd this year. Just to put how much that matters in context, let’s list the Texans’ drives from Sunday in order of the distance from the end zone on its opening play, and note what happened to end those drives:

• Punt
• Punt
• Punt
• TD
• Punt
• Punt
• FG
• TD
• TD
• FG
• TD

Joe Flacco’s two interceptions both came on tipped passes and were unlucky, but he also threw a couple more into the hands of Houston defenders at the line of scrimmage and got lucky that they weren’t able to hold onto them. One included a pass to J.J. Watt on the Baltimore 3-yard line. In all, the Texans were able to defense 11 of Flacco’s 43 passes on the day.

Based on what I saw from Sunday, I think there are plenty of reasons to be concerned as to whether Baltimore’s defense will stay at their previous level. Although I’ve focused on the passing game, the Ravens weren’t able to hold up against Houston’s rushing attack, allowing in excess of five yards per carry to the combination of Foster, Ben Tate, and Justin Forsett. The passing game is more troubling because the Ravens might only be starting one above-average player in the secondary, and while Ed Reed is truly great, even he’s playing with a torn labrum. It’s no surprise that the Ravens rushed back Terrell Suggs from his Achilles tear; they desperately need a pass rush to cover for those guys, and while Suggs did pick up a sack and a knockdown in his first game back, he tired and lost effectiveness as the game went along. Baltimore will do better than this against an inferior offense, but considering the sorts of offenses likely to show up in the AFC playoffs, it’s unlikely that they’ll be able to hold up.