With Greg Toler's season-ending injury, the Cards need good play from A.J. Jefferson (20), Patrick Peterson (21) and Richard Marshall (31).
New defensive coordinator Ray Horton has spent most of his coaching career with the defensive backs, and he has spent a chunk of time with his new secondary imploring they understand how they are the last line of defense.
"The guys up front can miss a tackle or mess up," cornerback Richard Marshall said, "but the guys in the back, we can't. There is pressure to get the job done."
The pressure got a little more intense for the cornerbacks Monday, with the news starter Greg Toler was out for the season after tearing the anterior cruciate ligament in his left knee. Training camp opened with Toler and 2010 undrafted free agent A.J. Jefferson manning the starting jobs, although at the time there seemed to be a path in which No. 1 pick Patrick Peterson and veteran free-agent signee Marshall would end up with the first unit.
It became clear heading into the third preseason game that Jefferson and Toler would hold on to the job, until Toler got hurt. Whisenhunt wouldn't say who will be starting but there is a real possibility it will end up being Peterson and Jefferson, the Cards' pair of homegrown talents.
The Cardinals did add veteran Fred Bennett – who was released by Cincinnati a couple days ago – to the cornerback mix Monday, waiving-injured linebacker Brandon Sharpe (hamstring). Bennett has five career interceptions since coming into the league as a Texans' fourth-round draft pick in 2007.
Still, the Jefferson-Peterson-Marshall trio will probably be the one in which the team must now rely.
"It hurts to lose G.T.," said reserve cornerback Michael Adams, who is recovering from knee surgery. "But I still think we are pretty deep at corner."
Whisenhunt said the Cards will continue to rotate their top three and see "how it plays out." Jefferson caught the coaching staff's collective eye last season, and even without an offseason to show off, he has impressed. Peterson has further to go, but as seen with his interception return for a touchdown against the Chargers, his raw talent is something to behold.
It might have been nicer to have Toler around and allow Peterson to ease into a crucial role, but that's not available any longer.
"You get to a point where your young guys have to play, they have to step up," Whisenhunt said. "I definitely feel good about A.J. and his progress, and Patrick, there is no question he is a talented young player. He just needs to some time. If we are playing with those two guys it's because they have earned it, and I am OK with that."
Peterson said "I believe I am ready" to start, but understands why the coaches are bringing him along slowly and acknowledged he is learning multiple positions, including safety in sub-packages and the return game.
Adams is expected to return soon -- Adams said he still hoped to return Monday to practice and play in the opener -- and has experience as the dime back.
Playing in Horton's defense means many times corners are in man-to-man situations, trying to keep up while blitzes create pressure. Both Peterson and Jefferson ooze confidence, even while saying the right things. That can only help.
But as they improve, the rest of the defense has gained confidence in them, too. "The safeties aren't getting on me as much as they used to, so they are trusting me to do my job," Jefferson said with a smile and a glance over to the safeties sitting by their locker.
Marshall, meanwhile, has been a "very good pro," Whisenhunt said, and does have 32 starts in the 32 games of 2009 and 2010.
Even with Toler's injury, with the three options, "I don't think there's any panic," Whisenhunt said.