The Packers’ playoff appearances the past two years have dramatically illustrated how important cornerback depth is in today’s NFL.

In 2009, following Al Harris’ season-ending knee injury, the Packers struggled with a lack of depth at the position and saw their season go up in smoke in a five-touchdown torching by Arizona quarterback Kurt Warner.

This past season, undrafted rookie Sam Shields came out of nowhere – with just one college season at the position – to solidify the third corner spot behind Pro-Bowlers Tramon Williams and Charles Woodson, and his two interceptions in the NFC Championship helped propel the Packers to the Super Bowl title.

It’s a bit of an exaggeration to say the entire defense’s playoff fortunes hinged on that one improvement, but don’t underestimate how significant it was. The Bears may have experienced injury issues at quarterback in the playoffs, but the Packers still got past elite QBs Michael Vick, Matt Ryan and Ben Roethlisberger to win it all.

With that in mind, the Packers could be looking to draft a viable candidate for the next corner spot behind the Williams-Woodson-Shields trio. If any of those three should get hurt, avoiding a repeat of ’09 will require a reliable fill-in. A long-term replacement for the 34-year-old Woodson needs seasoning sooner rather than later, too. Whether either is on the current roster is up for debate.

The Packers survived injuries to Woodson and Shields in Super Bowl XLV mostly thanks to a key interception by Jarrett Bush, but in 2011 Bush will be entering his sixth season and has been given repeated attempts to nail down a job in the nickel and dime defenses before.

The same goes for Pat Lee and Brandon Underwood, though both are younger, have battled injuries and should continue to improve under cornerbacks coach Joe Whitt, Jr., if they stay healthy. Meanwhile, Josh Bell was placed on injured reserve in training camp and failed to play in a preseason game in 2010.

The biggest unknown in the mix could be Josh Gordy, a rookie last year who was signed to the practice squad in mid-September and brought up to the active roster in December. He played in just two games before moving to the inactive list for the entire postseason, but he has yet to go through a training camp or offseason program in Green Bay. The current labor situation isn’t doing him any favors.

It’s hard to pinpoint exactly where cornerback falls on the Packers’ list of priorities for this draft, but it’s probably above safety.

That’s provided Morgan Burnett, whom General Manager Ted Thompson traded up to select in the third round last year, recovers fully from his ACL injury. Burnett won the starting job alongside three-time Pro Bowler Nick Collins as a rookie but was lost for the year to a knee injury in week four.

Fortunately for the Packers, veteran Charlie Peprah was ready to step in and the defense didn’t slip. Some might argue the unit was even better with the Collins-Peprah tandem in the back end, and the new contract Peprah received less than a month after the Super Bowl perhaps speaks to that.

Either way, it should shape up as a good training camp battle between Peprah – who does nothing flashy but most things well – and Burnett – who will try to translate his college playmaking ability to the pros – for the starting spot. Regardless of the outcome, the Packers will feel good about their number three.

How the rest of the depth chart at safety shakes out will depend primarily on the futures of veterans Atari Bigby and Anthony Smith. They’ve both had injury troubles and are scheduled to be free agents.

If they aren’t around, then perhaps a draft pick and/or undrafted free agent will compete with practice-squad holdovers Anthony Levine and Michael Greco for the fourth spot.

Mike Spofford is a 1995 Masters graduate of the Medill School of Journalism at Northwestern University who worked as a sports reporter for two daily newspapers in Wisconsin, covering the Packers in Super Bowl XXXII. Spofford has been a packers.com staff writer since 2006.