Without Polamalu for nearly five full games this season, the Steelers allowed opponents a 95.0 passer rating. With Polamalu, the Steelers allow a 56.3 passer rating.
Of course, Polamalu will play Monday night in Denver, but Clark most likely will not. The Steelers won't make a public announcement on Clark's availability, but he's expected to be de-activated because of his health issues in high altitude.
Clark has missed 13 of the Steelers' 43 games over the last three seasons, and his absences haven't cost the Steelers nearly as much as Polamalu's absences.
Without taking into account the 2007 game in Denver where Clark played but struggled greatly, here's the statistical breakdown of the last three seasons:
* Without Polamalu only: opposing passer rating 89.1.
* Without Clark only: opposing passer rating 61.1.
* Without both safeties: opposing passer rating 85.6.
* With both safeties: opposing passer rating 67.2.
By the numbers, it would appear that a healthy Clark is actually a liability. But Clark has missed nine games in which Polamalu played (Steelers are 6-3 in those games), and seven of the nine games were quarterbacked by Bruce Gradkowski, Jason Campbell, an over-the-hill Steve McNair, Derek Anderson, Kellen Clemens and David Garrard (twice).
The Steelers have played well without Clark, and they'll be helped Monday night by a Denver Broncos offense that doesn't throw deep nearly as well as it did last season.
In 2008, the Broncos ranked 13th in yards per completion (11.8). They now rank 21st (11.0), and the stats of one of the top receiving duos in the NFL, Brandon Marshall and Eddie Royal, have fallen off dramatically.
Marshall, the 6-4, 230-pound receiver from Pittsburgh's Larimer section of East Liberty, averaged 103 catches at 12.6 per catch the last two seasons. This season he averages 10.8 yards per each of his 33 catches.
Royal, the rookie sensation who caught 91 passes at 10.8 per catch last season, has only 20 catches at a 7.9 clip this season.
New Broncos quarterback Kyle Orton has thrown only six passes longer than 30 yards in distance, and the only completion was the 87-yard desperation tip that won the opener. The Steelers, on the other hand, have completed 5 of 12 such passes.
Steelers defensive coordinator Dick LeBeau looked instead at another statistic.
"They're record's saying whatever they're doing is the right thing to do," he said of the 6-1 Broncos. "They throw a lot of screens, a lot of controlled, high-percentage passes with a great running game. They control the clock against people. They do a great job on offense."
They didn't last week. The Baltimore Ravens held the Broncos to 66 yards rushing while keeping both safeties deep the majority of the game. The strategy paid off on both ends, as the Broncos gained a season-low 4.11 yards per pass attempt.
The Ravens also exposed a Broncos' defensive weakness by using multiple-WR packages to target nickel backs Jack Williams and rookie Alphonso Smith. The Broncos addressed that problem Friday by signing 35-year-old cornerback Ty Law, who's expected to play Monday night.
If Law can play that well again, he'll help a Broncos pass rush that's led by Elvis Dumervil, a 5-foot-11, 250-pound outside linebacker in the team's 3-4 alignment. Dumervil leads the AFC with 10 sacks and will be helped Monday night by crowd noise and the potential to get under 6-foot-8 Steelers left tackle Max Starks.
"The good news is I have the opportunity to go against James (Harrison) every day in practice, so it's not that big of a difference," Starks said of the Steelers' 6-foot pass-rusher.
Harrison will be up against Broncos left tackle Ryan Clady, who was the only rookie voted to the All-Pro (second) team last season. More will be expected of Harrison's bookend, LaMarr Woodley, who'll face Tyler Polumbus, a first-time starter who stepped in last week for injured starter Ryan Harris at right tackle.
"It's not going to be easy there," the Steelers' Brett Keisel said of playing in Denver on Monday night. "It's going to be a ruckus. It really is. They're going to come out swinging. We're just going to have to keep throwing punches, too."