Winfield is the veteran-most player of the quartet. With 14 years experience in the league, he is still playing at a Pro Bowl level.
"There aren't many 35-year-old corners playing at his level," said Vikings' coach Leslie Frazier this week. "It's very good for our team. It's amazing to see what he's done. He's been so productive throughout the season and he stayed healthy, which over the last two to three years hasn't always been the case, so it's good to see."
Cobb, despite being 13 years younger than Winfield, understands that he could be in for his toughest one-on-one challenge this season.
"He's a veteran guy. He's been through a lot," said Cobb. "He knows different kinds of players. He plays against Percy (in practice) all the time so, I mean, we're a lot of the same player, so I'm sure he'll be ready to play. He's a big, physical guy that likes to hit. It's going to be a tough day but we're going to go out there and game plan off of it and go out there and try to execute our game plan."
Execution has been at the highest levels between Cobb and quarterback Aaron Rodgers this season. Cobb is No. 3 in the league in catches from the slot with 43 (out of 57 targets), good for a catch rate of 75.4 percent. That percentage is second only to the Denver Broncos' Brandon Stokley among those receivers who have played at least 50 percent of their snaps from the slot. If not for Cobb's six dropped passes in slot duty, he would be ahead of Stokley's 80 percent mark.
On the other side, Winfield has made yards and completions tough to come by. Opposing quarterbacks have a 74.7 passer rating throwing his way when he is covering the slot receiver, and he has yet to give up a touchdown.
Cobb is well aware of Winfield's physical reputation, but in his limited film study of the 5-foot-9, 180-pound cornerback, he sees mental qualities, too, that make a great inside defender.
"Being able to read route concepts," said Cobb. "He has a great understanding of zone coverages and reading route concepts and making plays. He makes some plays. Like I said, he's a veteran guy with a lot of experience. He's seen a lot. So, he understands the game."
Hayward, just a rookie, has displayed similar qualities playing the nickel cornerback spot for the Packers. Though he has 76 fewer snaps covering the slot receiver than Winfield's league-leading 232 (in 11 games), his performance has been better.
Like Winfield, Hayward has yet to give up a touchdown. But his 53.0 passer rating allowed when covering the slot is No. 1 in the NFL among those cornerbacks who have played at least 50 percent of their team's snaps.
Even more remarkable, Hayward has not drawn a penalty in 446 total plays on defense. His five interceptions are tied for second best in the league and his 18 passes defended (according to team statistics) leads the Packers.
"I think I am a complete corner," Hayward said on Friday. "I play in and out. I've been proving that. I got some of my picks outside, got some inside, I've made plays inside and made plays outside."
The wild card in Sunday's slot battles will be Harvin. The Vikings' top playmaker was having a Pro Bowl season until an ankle injury slowed it. Over the first nine games, he racked up 62 catches, often serving as an extension of the running game.
Like Cobb, Harvin has an impressive catch rate - 74.3 percent - without any dropped passes out of the slot. Despite missing the last two games, he leads the NFL in yards after the catch with 551, according to STATS.
After not practicing for the past three weeks (which included a bye week), Harvin returned to practice Wednesday as a limited participant but did not practice on Thursday or Friday. Frazier listed Harvin as doubtful because of his difficult cutting and changing direction, making him a long shot to play.
(Note: All statistics in this story according to ProFootballFocus.com unless otherwise noted)
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Matt Tevsh has covered the Packers since 1996. E-mail him at firstname.lastname@example.org