EDEN PRAIRIE, Minn. -- Greg Jennings was working late after Minnesota Vikings practice this week, helping teammates prepare for Sunday's regular-season opener at Detroit.
For at least 20 minutes, Jennings stayed on the field but quarterback Christian Ponder and the other receivers were nowhere to be seen. Jennings had the ear of rookie cornerback Xavier Rhodes, working on different technique and offering tips. Later, safety Jamarca Sanford joined in to pick Jennings' brain.
Jennings, the eight-year veteran in his first season with Minnesota, seems to understand -- aside from quarterback Christian Ponder -- the Vikings' success hinges on the development of Rhodes and the rest of the team's young cornerbacks. Rhodes, getting set for his first NFL regular-season game after being taken with the 25th overall pick in April's draft, is trying to soak in as much knowledge as he can before facing the Lions and their potent passing attack.
"He's giving me tips and reminders and stuff like that, so I can be on my toes and what to look for," Rhodes said, adding that he leans on the tutelage of Jennings and cornerback Chris Cook. "It's very valuable because they know what a receiver is doing, they know a receiver's tendencies . . . Receivers watch other receivers to get something from their game to add to theirs. We watch and sometimes we don't understand what he's doing, so I go ask a receiver and the receiver will tell me and I'll have a better understanding."
When Minnesota released 14-year veteran Antoine Winfield in the offseason, the team's cornerbacks became the biggest unknown on a team trying to prove last year's playoff appearance was a trend and not an aberration.
Cook, 26, is suddenly the wise, old veteran of the group. Rhodes is the big (6-foot-2, 210 pounds) corner who loves to play in press coverage. Josh Robinson, a 2012 third-round pick, is actually the youngest of the group at 22 years old and is currently Winfield's replacement on the outside in the base defense and the slot when the team brings in Rhodes as the third cornerback. The team's five cornerbacks average 24.2 years old.
"They're three young guys who want to get better and just want to show this league they can be elite in this league," Sanford said of Cook, Robinson and Rhodes. "I like all three of them and ready to go to war with all three. All three want to get better and what I like about Cook and Xavier, they're really big and long and can run. Josh is really the speedster on the team and he's a big hitter also. I don't think he gets too much credit for that.
"We got a great secondary and we're just looking forward to going out and showing everybody we're here to make some noise this year in the league."
Winfield, 36, was the trusted leader who was the rock in Minnesota's secondary for years. Cook is entering his fourth year in the league but has played only 22 career games and is still looking for his first interception. Sanford, 28, is the oldest member of the secondary and Harrison Smith, last year's revelation as the other starting safety, is 24 years old.
Even without Winfield, who is currently retired after being released by Seattle, the Vikings are confident in the group they've assembled.
"I don't think we took one step back when Antoine left," Robinson said. "We knew he was a good guy, but we knew that we had a lot of ability in that room and we're continuing to go with that and work at the things we need to improve on."
Inexperience -- and health in Cook's case -- is what creates the concern. Minnesota has 70 career games among its top four cornerbacks, including A.J. Jefferson. Winfield played 119 games in his nine years with the Vikings. Robinson was 8 years old when Winfield broke into the league.
The group is talented, confident and is eager to prove itself.
"Once we put those things on tape, it will be known real quick," Robinson said.
Sunday is right around the corner and the tape will be telling. The cornerbacks get the chance against the league's top receiver. Detroit's Calvin Johnson is coming off an NFL-record 1,964 receiving yards last season and is one of the reasons Minnesota has drafted a pair of tall corners in Cook and Rhodes.
Johnson is 6-foot-5, 236 pounds and fast. He had 12 catches for 207 yards and a touchdown in the final meeting between the two teams last season. But that was without Cook in the lineup because of a broken arm, another season for the 6-foot-2 Cook that was disrupted by injury.
Cook relishes the chance to match up against Johnson and will likely draw the assignment often on Sunday. In the first game between the two teams last season, Cook was partially responsible for slowing Johnson to five catches and 54 yards.
"He brings out the best in me, being the best receiver in the league today," Cook said. "It's seeing where my bar is set right now, especially going against him."
The Vikings also hit Johnson when they got the chance. Linebacker Chad Greenway applied a big hit over the middle. Sanford and Smith sandwiched him on a hit in the end zone to break up a possible touchdown. Expect a similar game plan this time.
But Detroit also sees the inexperience in Minnesota's secondary and with Rhodes likely to play a big role in his first game.
"We've got to take advantage of any inexperience," Johnson said of Rhodes this week. "He may be a great player or what-not, but experience means a lot on Sundays."
Experience on Sundays is what the Vikings are trying to acquire, while proving to the rest of the league the secondary is no weak link.
"Most corners have that about them that they want to prove that they can shut somebody down, and it's no different from any guy in our secondary room," Robinson said. "We all have that confidence and all of us have the ability, we've just got to go out there and put it on tape."
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