JERSEY CITY, N.J. -- Percy Harvin is the unknown quantity of the Seahawks' offense, as much an X-factor as there has ever been in the Super Bowl, given his paucity of experience in a Seahawks uniform.
The Broncos can only consult limited Seahawks tape, and have to evaluate his Vikings work, as well as Seattle's own tendencies to figure out how to combat the presence of Harvin, who could see more touches to date than in his entire, injury-plagued 2013 season to date.
But the Harvin factor is not the only question about the way Seattle might choose to attack the Denver defense, which has become increasingly stout on the inside with the breakthrough play of Terrance Knighton and his ability to free linebackers Danny Trevathan and Paris Lenon to contain the run and fill the gaps.
That might lead the Seahawks to try to test the Broncos outside the tackles and in space, and could lead back to quarterback Russell Wilson exercising the run option of his potent dual threat.
Running has never been what Wilson would prefer to do; it's a choice he has, but it's one he'd prefer to eschew in favor of beating teams with his right arm, which has held his career carries-per-game average to 5.9 -- which has been just 3.75 per game in the Seahawks' last four contests. He has gained just 21 yards on nine non-kneeldown carries in Seattle's last three games -- all of which have seen Seattle run at least as often as it throws.
"I think he's been smart about how he runs," said Broncos Defensive Coordinator Jack Del Rio. "He's not taking unnecessary risks. He's not exposing himself to unnecessary contact. He's a threat to run but he's not trying to run over people to prove a point.
"And really the thing he does very well is as he's running his eyes are constantly down the field and he's prepared to throw the ball down the field, so that's been a big emphasis point for us."
And that's where the Broncos' defensive effort could turn into a feast-or-famine contrast. Wilson waits for late-opening receivers better than almost anyone in the game, using his adeptness in rollout situations to buy time for his receivers to get open. This puts a unique challenge on Denver's cornerbacks and safeties, who will have to maintain coverage integrity up to as many as eight to 10 seconds after the snap.
In Week 5, Dallas quarterback Tony Romo took advantage of this -- along with a Broncos secondary depleted by injuries -- by darting around the backfield to buy time for his targets, led by wide receivers Doug Baldwin and Golden Tate, whose statistics were comparable. Neither broke 1,000 receiving yards, but each had between 50 and 65 receptions and precisely five touchdown catches.
"They work well with their quarterback," said cornerback Dominique Rodgers-Cromartie. "They extend their routes. They have speed, they are very aggressive to the ball and they can make you miss. Golden Tate (Doug) Baldwin, Percy Harvin…those are capable guys even though a lot of people aren't talking about them. As defenders, we know. You can't take those guys lightly."
In part because Wilson holds the football to give his receivers extra time to freelance and get open, the second-year quarterback has been hit often when he decides to pass -- once every 4.99 pass plays, the most in the league. (Peyton Manning and the Broncos are at the opposite end of this statistic; he and Brock Osweiler have been hit one every 13.6 pass plays, the best rate in the league and well above the league average of one hit every 7.44 pass plays.) The sack rate of one every 10.5 pass plays is also the most extreme in the NFL.
"He keeps his eyes downfield," defensive end Shaun Phillips said. "With a guy like that, they are never completely out of the play just because of the fact that he is do dynamic in throwing the ball and running it. He has a big, strong arm as well."
The desire to use Wilson's legs as a threat could lead to some zone-read looks. Those would also change the formations out of which running back Marshawn Lynch runs, but unlike the rest of their offense, no such questions exist about No. 24 -- besides queries about his Media Day conduct.
Lynch is arguably the most effective running back in the NFL at forcing missed tackles; if he does that Sunday, he will effectively turn a recent Broncos strength into a weakness.
"He doesn't stop running hard," said defensive tackle Terrance Knighton. "You can hit him in the backfield, and he can turn a minus-two into a plus-seven.
"And usually a lot of times guys will have him wrapped up, and guys aren't running to the ball, aren't gang-tackling, and he'll break out of a tackle. So the challenge for us is, every play, to have 11 guys to the ball, and make sure we get the guy down."
Added Phillips: "I think the main thing about him is the fact that he doesn't want to go down and he doesn't go down. He's a very hard runner. He wants to deliver the blow instead of take the blow. You have to respect a guy like that."
When Lynch has at least 109 yards, which was his total against the 49ers in the NFC Championship Game, the Seahawks usually win; they are 15-3 when he hits that number, including 4-0 in the postseason.
"There has to be a whole swarm of our defensive players tackling him and taking him down," said linebacker Nate Irving.
Harvin, Wilson and Lynch. Each is capable of seizing the game for himself. Some learning on the fly and adapting may be necessary to contain all three Sunday night.