The Steelers are more used to playing without Troy Polamalu than they'd like -- he missed 11 games in 2009 and four already this season. They might feel Polamalu's absence a bit more this coming Sunday, though.
The reason: Robert Griffin III.
Washington's offense is different from any the Steelers have seen this season. The closest comparison for Pittsburgh in recent memory? Denver's Tim Tebow-led attack that Pittsburgh dealt with in the 2011 playoffs. Only Griffin has more than twice as many passing attempts (133) as he does runs (64), and a great deal of the Washington offense is designed to open up holes for Alfred Morris.
The Redskins rely on a lot of misdirection -- constant motion and the frequent use of Griffin in zone-read situations help Washington create spaces in the defense. Griffin's dual-threat ability has to stay at the front of the opposing defenders' minds.
One way to neutralize such an attack is by having a player capable of spying the quarterback and handling him one-on-one. Polamalu, with his versatile set of skills, is someone who might have been up to the task.
So, Mike Tomlin's announcement Monday that Polamalu will not play in Week 8 (and it's a horrible sign for Polamalu's health that he's being ruled out already) leaves the Steelers without that matchup option.
Will Allen, prior to suffering an ankle injury of his own in Cincinnati, replaced Polamalu at strong safety. Allen will again play that role against Washington. He's a nine-year vet with two starts under his belt this season. But he also has all of 11 tackles this year with the Steelers, and he has carved out more of a niche as a special teams player than a star defender.
In other words, Pittsburgh can ask him only to hold down the fort in Polamalu's absence, not to replace the dynamic safety. The same goes for Ryan Mundy, who took over for an injured Allen last week.
The Steelers have to be much less aggressive with their safety play minus Polamalu, which puts more pressure on the front seven. That could be a recipe for disaster against the Redskins.
Pittsburgh's defensive line has underachieved this season, with Casey Hampton and Ziggy Hood taking the bulk of the criticism. The linebackers have been up and down, too, especially when LaMarr Woodley's had to sit.
Griffin's presence in the Redskins' offense forces the defense into a ton of read-and-react situations, be it with Griffin rolling out, taking off on designed runs, using play-action to set up a pocket or handing off to one of his backs. Defenses have to be aware of every option at the snap, then try to outguess Griffin once the ball is in play.
A healthy Polamalu is as good as they come in that aspect of the game -- few players, especially at the safety spot, can pick their spots like Polamalu does.
Without him, the Steelers will have to play softer coverage against Griffin and try to rely on guys like Woodley and a declining James Harrison to set the edge so the inside linebackers and safeties can focus on the middle of the field.