It is a scary thought, considering the Saints' defense already had more problems against the Seahawks in that 34-7 loss in Week 13 than it has had against any other offense all season. The teams meet again Saturday in the playoffs.
"I know he's an elite player when he's healthy, so absolutely [he adds a degree of difficulty]," Saints defensive coordinator Rob Ryan said of Harvin, a fast and elusive receiver who has played in only one game this season because of a lingering hip injury. "He's had a couple weeks to get healthy and get back with [offensive coordinator Darrell] Bevell and that offense, and they do a great job. And they do a hell of a job of using all of his talents. One time he's lining up at running back and at receiver. And hell, they'll put him at center, probably, and hike the ball. So he's all over the place.
The Saints know they will have to keep track of versatile Seattle receiver Percy Harvin on Saturday.
"We know who he is, and we'll have him identified, and we'll do a great job."
Added Saints safety Malcolm Jenkins: "He definitely adds a lot of unknown to their offense. And he accounts for a lot of explosive plays when he's in there. So I'm sure we'll see something exotic with him."
Saints outside linebacker Junior Galette, however, insisted that he isn't worried about Harvin's presence, because he has so much faith in the way cornerback Keenan Lewis has performed against top receivers throughout this season. Lewis is expected to play Saturday, despite suffering a concussion last week.
"We have Keenan Lewis, who's been shutting guys down all year," Galette said. "So we probably won't see much of [Harvin]."
With or without Harvin, the Seahawks create some of the most unique challenges in the league for opposing defenses.
Quarterback Russell Wilson is elusive, and he is just as dangerous throwing outside of the pocket as he is running the ball -- a painful lesson the Saints learned time and time again in that first meeting, when he threw for 310 yards and three touchdowns, and ran eight times for 47 yards.
Meanwhile, the Seahawks also feature one of the league's most punishing runners in Marshawn Lynch, who breaks a ton of tackles and becomes even harder to stop once he reaches the second level of the defense (another painful lesson the Saints learned, this time during the infamous "BeastQuake" run in their Jan. 8, 2011, playoff meeting).
The Saints admittedly focused too much on containing Lynch in the first meeting this season. They did hold him to 45 yards on 16 carries, but they overreacted to him at times and made more discipline errors than they have in any other game this season. A lot of the Seahawks' big plays came off play-action fakes or when the Saints overpursued in the backfield.
"We had aggressively planned on attacking their run game, which we did for the most part," Ryan said. "But anything other than that, we did not execute very well.”
When asked what the Saints learned from that first meeting, Ryan said, "Pretty much everything."
"We really didn't play our style of game at all," Ryan said. "I think that's really the only game that I just don't think we were ourselves at all. Whatever it was, we made mental mistakes, we made fundamental mistakes, some technique things. We pride ourselves on playing the game the right way. I don't think we really did that.
"Obviously the execution of their quarterback was something to be seen. Hopefully he doesn't have that type of game against us again, or we're in big trouble."
Galette said the Saints did learn from those mistakes. He said it was a confidence boost for the Saints when they played much more disciplined and effective against the Carolina Panthers and quarterback Cam Newton in Weeks 14 and 16 (a 31-13 victory and a 17-13 loss).