The Pittsburgh Steelers will be without safety Troy Polamalu this Thursday when the team travels to Tennessee to face the Titans. Polamalu re-aggravated a calf injury that held him out of the previous two games, and he could be off the field for far longer than just this one game.
Polamalu is one of the most well-known players on the Steelers roster—and that's beyond the numerous endorsement deals that have slapped his face across television screens in recent years. It all starts with how he plays his position—something he's done so well that he's practically reinvented what being a strong safety means in the NFL.
Obviously, the Steelers will have to do a lot of work to make up for Polamalu's absence, and it's something they are acutely familiar with. Regardless, the Steelers have dropped nearly half of all games in which Polamalu has been sidelined (as compared to 72 percent when he's there). Why is this? What does Polamalu bring to the table that cannot be replicated when he's out of the game? Let's take a closer look.
The point of the safety position, especially strong safety, is to be a versatile defender with the ability to cover and tackle receivers, stop running backs before they can break out big gains as well as rush the passer. This versatility allows for safeties to be unpredictable, and thus dangerous, and none in the league possesses those traits as much as Troy Polamalu.
Polamalu can stand on the line of scrimmage, only to dart backwards and help out in pass coverage. He can dart forward, in a blitz or he can stand pat to snag the running back heading into his direction. Or, he can start in the middle of the field and move both sideways and towards the quarterback or running back, and notch himself a sack or a tackle for loss.
His unpredictability requires opposing quarterbacks to always be aware of where he is on the field and what he might do, and hopefully adjust the play accordingly. However, this isn't all that successful all of the time—Polamalu is too elusive and too fast to assume he'll stay in one place for long and too experienced to be able to predict what he's thinking or seeing.
Just the simple fact that Polamalu requires opposing offenses to change their approaches based solely on his presence and location on the field means that without him, quarterbacks are simply less afraid of the Steelers defense.
That's not always a bad thing—the Steelers can easily take advantage of a quarterback and offense that is more relaxed without Polamalu. But at the same time, Polamalu has earned his reputation because of how he's played over the course of his career, and clearly, a safety who garners this much attention from the offense he's trying to stop cannot easily be replaced.
It's easy to know which Steelers linebackers will drop back in coverage and which will rush the passer. It's easy to see who is going to come up and stop the running back and who is going to try to keep the offensive line from effectively blocking a hole.
Without Polamalu, there's no one with the speed to show blitz, react to the play being changed to a run and come up and make the tackle when any other player would have been stopped without having the chance.
When fellow safety Ryan Clark complained of the Steelers defense looking "predictable" against the Oakland Raiders, part of what he was saying is that they needed Polamalu out there to add that dimension of danger. Without him, they need to play a strong, traditional defense.
A Safety to Stop the Run
Both Polamalu and Clark play major roles in the Steelers run defense, and without Polamalu on the field—and Ryan Mundy in his place—that area of their game takes a hit.
According to Pro Football Focus (subscription required), both Polamalu and Clark have positive grades in stopping the run (so does Will Allen, though it's not as pronounced as the two starters'), while only the Philadelphia Eagles' Kurt Coleman grades out worse against the run than Mundy.
As mentioned above, Polamalu has the speed to appear like he's covering the middle of the field and then is able to rush forward upon the opposing offense snapping the ball, step up and tackle the running back before anyone knows what is happening. He's also a good clean-up man, picking up tackles other Steelers defenders have missed.
If Clark moves up and Polamalu isn't playing, it's clear that Clark is there to stop the run and quarterbacks can adjust to a pass. Mundy doesn't have the speed nor tackling ability to take over the bulk of Polamalu's run assignments successfully, so the Steelers often have to keep the two in the middle of the field or deeper simply because otherwise, they'd tip their hand that they are expecting the run, and throwing Mundy up front is too much of a liability.
That means that the defensive front seven have to separate off their blocks and tackle the running back, corners have to play shorter and the Steelers lose a dimension to their defense. Or, they have to roll the dice and hope that Mundy can make a play rather than miss a tackle or draw a penalty.
In his less than two games, Polamalu has eight tackles and none missed; Mundy has 16 tackles and six misses. Even if Mundy is asked to take on running backs, the odds are fairly high he won't make the tackle. It's hugely risky to assume that Mundy can fill Polamalu's considerable shoes.
Ryan Mundy or Will Allen?
It's such a risk, in fact, that when Steelers head coach Mike Tomlin confirmed on Monday that Polamalu will not play on Thursday against the Titans, it may in fact be Will Allen and not Ryan Mundy who gets the start in his stead.
Mundy isn't just terrible against the run, he's also a major risk in pass coverage. Polamalu hasn't been much used as a traditional pass-defending member of the secondary—rather, he prowls the depths and uses his speed to get to a receiver or his eyes to jump routes and pull down interceptions.
Mundy is less dynamic overall, and thus, when in coverage, is assigned a specific man or zone and acts more like a free safety than a Polamalu-type player. Still, even when performing this more limited role, Mundy hasn't stepped up. He's given up nine receptions so far this year—15th-most in the league—and three touchdowns, the most of any safety.
Opposing quarterbacks have a 123.6 passer rating when throwing to the receiver assigned to him, and further, when Mundy goes for a tackle, he has repeatedly launched himself at the receivers' heads, drawing penalties and fines and knocking players out of games.
It's damaging to the Steelers' bottom line to rely so heavily on Mundy, and it's frankly dangerous for opposing receivers when he's coming at them to make tackles. But moving on to Allen has its drawbacks as well.
Allen has played just two snaps so far this season, both times in run support, with one assisted tackle to his name. He was on the field for eight snaps last year (five vs. the run, three vs. the pass), and his most active year was 2009, when he played 199 snaps, with 111 against the run and 86 in pass coverage, when he ranked 156th out of 189 safeties, according to Pro Football Focus.
While it helps that his profile is more similar to that of Polamalu's, he does lack the pass rush background that makes the starter so dangerous. So does Mundy, to be sure, and the simple fact that we've seen more of him and it's been little so underwhelming does present a strong argument for Allen to take his job.
But no matter what the Steelers decide, they'll still be lacking a major component of what has made their defense one of the best in the league, season after season. There are no perfect replacements, no ideal situation the Steelers can find to step in for Polamalu, it's simply about guessing at the lesser of two evils and hoping they are correct.