For the second straight season, the Pittsburgh Steelers defense ended the year as the top squad in the league in yards allowed, while again being a top-five team in points given up per game. Despite star players advancing in age and injuries pockmarking the season, the Steelers' reputation for being one of the best defensive football teams in the league remained intact in 2012.
However, those impressive numbers don't tell the entire story of the Steelers defense over the course of the season. Let's take a closer look at how Pittsburgh's defense fared this year and some of the biggest storylines that emerged on that side of the ball.
The Defensive Line
When it comes to injuries and performance stability, the Steelers defensive line fared the best of any of their positional groups in 2012. Nose tackle Casey Hampton started all 16 games after tearing his ACL in the team's Wild Card playoff loss to the Denver Broncos in the previous season and he was joined by defensive ends Ziggy Hood and Brett Keisel for the totality of the season.
That's not to say that Hood, Keisel and Hampton played every defensive snap in 2012, however. Backup nose tackle Steve McLendon played 139 snaps to Hampton's 503 and spent the slight majority of his time in pass rushing situations, which netted him three sacks.
With 887 snaps, Keisel had the most playing time on the defensive line, at right end, though 2011 draft pick Cameron Heyward also saw time at the position, primarily in the first half of the season. In the second half, he spelled Hood most often, adding assistance in the pass rush, where he spent 151 of his 267 total snaps.
In a 3-4 defense, like the one the Steelers run, the defensive line often takes a backseat to the more visible linebackers, who are responsible for both pass rushing and coverage duties. Still, the pass rush depends heavily on the defensive line, who need to occupy offensive linemen, push them back and create gaps through which the linebackers can reach the quarterback. They also provide front-line pass defense help as well—for example the three batted passes apiece that Hood and Keisel had on the season.
As a pass rusher, Keisel was pretty successful, with five sacks, six hits and 23 pressures on the year (according to Pro Football Focus) but his run defense skills slipped from their 2011 numbers—he had just 21 tackles and 16 stops on his 331 snaps against the run.
Hood didn't fare much better against the run, either, with 23 tackles and 15 stops on his 302 run snaps. More than any member of the Steelers defensive line, Hood was often pushed back by the offensive linemen he was trying to contain—which explains why he spent the latter half of the season splitting more and more time with Heyward.
Heyward played only 107 run snaps in 2012, but he recorded a stop 9.3 percent of the time. Considering Keisel's age and how Hood has been relatively disappointing in his time in Pittsburgh and it looks as though Heyward may have a future as a starter as early as 2013.
Regardless, the Steelers defense ended the season ranking second in rushing yards allowed per game, at 90.6; granted teams only ran against them an average of 24.4 times per game, and the defensive line isn't solely responsible for run-stopping, but how the defensive linemen handle their offensive counterparts plays the first role in whether or not a run gains or loses yards. In this area, Keisel, McLendon, Hood, Heyward and Hampton performed their jobs well.
Only in the pass rush was the defensive line deficient. Hampton, at age 36 and coming off of knee surgery, could handle a double-team of offensive linemen well when it came to the run game, but couldn't get enough push-back in pass rushing situations. The same goes for Hood.
Heyward, McLendon and Keisel graded out the best in the pass rush for the Steelers this season, but with only one of those men considered a starter, it's clearly an area the Steelers must examine this offseason. The Steelers notched just 37 sacks this season, and the responsibility falls equally to the defensive line and the linebackers.
As just mentioned, the Steelers had only 37 sacks in 2012—that's up from their total of 35 in 2011, but well below the league-leading 48 they had in 2010. Though pass rushing problems with their defensive line played a part in this, their linebackers too underperformed in this extremely important area. Injuries were one reason for this.
Right outside linebacker James Harrison didn't take the field until Week 5 after dealing with a knee injury throughout much of the spring and summer, while left outside backer LaMarr Woodley missed three games, first because of a re-aggravation of the right hamstring injury that saw him miss time in 2011 and then an ankle injury later in the year.
With Woodley under 100 percent health when he was on the field, the Steelers' pass rush suffered. Harrison's knee as well as his age also kept him from being as effective as he's been in the past. And with inside linebackers Lawrence Timmons and Larry Foote more responsible for run-stopping and coverage, the Steelers simply couldn't get to opposing quarterbacks as they used to.
To help bolster their pass rush, Jason Worilds and to a lesser extent, Chris Carter, saw time in the defensive rotation. Worilds played a total of 435 snaps in 2012, with 177 of those against the run and 175 in the pass rush.
He appeared in 13 games—three as the right outside backer and 10 on the left, with three starts in place of Woodley and amassed four sacks (five, according to ESPN), four quarterback hits and eight hurries, making him just slightly less effective in pass rushing situations than other linebackers with similar snap totals.
Carter played 104 snaps and appeared in four games, starting at the right side in place of Harrison in the first three weeks of the season and then playing just one snap in Week 8. He was used primarily in run defense, however, and had no quarterback pressures on the year.
In terms of all-around performance, Timmons was Pittsburgh's best linebacker on the season. He was their second-leading tackler, with 106, had six sacks, 10 quarterback hits, 12 hurries and 54 total defensive stops, as well as two forced fumbles and three interceptions, one for a touchdown.
He was joined on the inside by Larry Foote, who took over for James Farrior. Foote, however, didn't fare as well as Timmons. He had no interceptions and gave up four touchdowns on the season when in coverage, though he was the team leader in tackles and also had two forced fumbles and four sacks.
As run-stoppers, Foote and Timmons were exactly even, with the same amount of run defense snaps and the same stop percentage, but Foote also had nine total missed tackles on the season—or one for every 11.8 he made (Timmons had a missed tackle for every 20.4 he made, ranking him fifth overall in tackling efficiency among inside linebackers).
Whether the issue is youth, health or speed, the Steelers will need to make some changes in their linebacker corps, or use a more rotational approach in 2013, in order to improve their pass rushing efficiency. Overall, Pittsburgh's defense ranked last in the league in pass rush, according to Pro Football Focus. Though this isn't solely the fault of the linebackers, in a 3-4 defense they're the ones most responsible for bringing pressure and they certainly didn't do a good enough job of it in 2012.
When talking about personnel instability for the Steelers defense, their secondary led the way in the 2012 season. Injuries, again, had something to do with this, but inconsistent play also forced their hands in roster matters.
Safety Troy Polamalu's lingering calf injury had him miss seven games over the course of the season, with him not getting fully healthy until Week 13. At first, he was replaced by Ryan Mundy, who started in the first three games before getting only situational work over the course of nine others.
Mundy's snaps sunk to the single digits in all but two games after Week 6, thanks to giving up three touchdowns over the first four games. He allowed 10 of the 14 passes thrown his way on the season to be caught by their intended receivers. Considering that performance, it's not surprising that he was replaced by Will Allen, who started at strong safety from Weeks 6 through 12.
In Allen's 432 total snaps, he was thrown to only 10 times, with just four of those passes caught. Though he had no interceptions, he defended two passes and gave up no touchdowns. In fact, teams were simply unwilling to throw his direction, making him an immediate upgrade over Mundy, who was more heavily tested despite playing fewer snaps.
Without question, Pittsburgh's best safety—and most valuable member of their secondary—was free safety Ryan Clark. Clark ended the year as Pro Football Focus' ninth-ranked safety, thanks to his 102 total tackles and allowing just 143 receiving yards on 19 completions. He also gave up no touchdowns, had two interceptions, defended three passes and opposing quarterbacks throwing his way averaged just a 48.5 rating.
When Polamalu did return, he did manage to be effective. Though he played only 402 snaps—157 against the run, 14 in pass rush and 231 in coverage—he still ranked 13th among safeties, putting up a sack, three quarterback hurries and an interception while allowing just 45.5 percent of passes thrown his way to be completed.
At cornerback, the Steelers also had to do a bit of player rotation. Ike Taylor and Keenan Lewis got the start on the outside, with Taylor missing the final weeks of the season with an ankle injury. Taylor's season got off to a rocky start, giving up five touchdowns in the Steelers first six games, but he allowed no others in the remainder of the year and receivers under his watch only pulled down 44.1 percent of the passes thrown to them.
Lewis fared even better on the left side of the field, giving up only three touchdowns on the season, though he had no interceptions. He allowed a few more completions than Taylor—59 on 112 targets—but opposing quarterbacks still had just an 80.7 passer rating when throwing his direction.
Lewis and Taylor were helped out by Cortez Allen, who played 563 total snaps, mainly as the slot or nickel corner (though he did take over for Taylor as starter after Taylor's injury). Cortez gave up just a single touchdown in 2012 and had two interceptions and gave up completions on just 58.4 percent of the 77 passes thrown his direction.
Curtis Brown and Josh Victorian also saw time at cornerback. Victorian had one start, in Week 15, as left cornerback and saw time on both the right and the left in the final four weeks of the season, giving up one touchdown in that time. Brown played 84 total snaps over eight games, but the fact that he allowed receptions on 73.3 percent of the passes thrown his way demonstrates why he didn't get more time.
The real problem plaguing the Steelers secondary this season was interceptions. As a team, Pittsburgh had just 10 total picks on the year, ranking them 27th in the league. A number of likely interceptions were dropped on a near-weekly basis. Though coverage was good—the Steelers were tops in the league in passing yards allowed per game—without the turnovers, they weren't as fearsome.