Ravens coach Brian Billick knew his trip to the Super Bowl would have its price.

One of the best defenses assembled in NFL history is about to be picked apart once free agency begins on Friday.

	Baltimore's Jamie Sharper tops the list of free agent linebackers.

Billick could lose linebackers Jamie Sharper and Cornell Brown along with safeties Kim Herring and Rod Woodson, who won't have his $3 million option renewed. The Ravens' plan is to battle to keep Brown, Herring and Woodson, but they know Sharper's value soared into the $4 million-plus range.

The amazing thing about the defensive players available in free agency is that many of the top ones are in their mid-20s and are high-round draft choices. That's rare.

Look at the defensive ends. Teams crave pass rushers, and 10-sack seasons could be gained by signing Simeon Rice of the Cardinals, Marcellus Wiley of the Bills, Kenny Holmes of the Titans and longtime veteran Trace Armstrong of the Dolphins.

The list of free agent defensive tackles isn't as deep. Chad Eaton of the Patriots tops the list because of his hustle and could be a perfect fit for the Seahawks. Bryan Robinson of the Bears could play end or tackle, but he'll probably stay with the Bears because they placed the transition designation on him to match any offer. The big names at tackle, though, will pass through the waiver wire: Chester McGlockton of the Chiefs, Cortez Kennedy of the Seahawks, Ted Washington of the Bills and D'Marco Farr of the Rams.

For impact, it's hard to top the linebacker position. It wouldn't be surprising to see a team pay the $4 million plus to get the Ravens' Jamie Sharper and move him to middle linebacker because of his range.

John Mobley of the Broncos, Dwayne Rudd of the Vikings, Dexter Coakley of the Cowboys, Shawn Barber of the Redskins and Derrick Rodgers of the Dolphins fill out an impressive list of young linebackers who have mobility.

Expect Browns coach Butch Davis to sign at least one from this group. The list grows even more impressive if the Bills cut Sam Rogers and the Saints cut Pro Bowl linebacker Mark Fields.

Middle linebacker isn't as deep, but Derek Smith of the Redskins, Darrin Smith of the Saints and Henri Crockett of the Falcons will draw the most interest.

Complicating free agency is the $36 million contract given to cornerback Ray Buchanan of the Falcons and the $30 million contract given to safety Darren Sharper of the Packers.

Buchanan's contract makes it tougher for the Giants to re-sign Jason Sehorn, but they should get a deal done. Panthers safety Mike Minter is a different story. Panthers coach George Seifert knows that Minter could head to Indianapolis and reunite with Bill Polian, who drafted him, but paying more than $4 million a year for a safety isn't in the Panthers' budget.

With Buchanan, Cardinals franchise player Aeneas Williams and probably Sehorn off the market, Ronde Barber of the Buccaneers, Denard Walker of the Titans, Walt Harris of the Bears and Terrell Buckley of the Broncos are the best available cornerbacks.

The Ravens' Herring is the young safety teams such as the Saints and Colts will be studying. Watch for new Jets coach Herm Edwards to try to bring Bucs safety Damien Robinson to Gotham. For experience, it's hard to top Pro Bowl safety Brock Marion, whom the Dolphins hope to re-sign, and the Ravens' Woodson.

John Clayton is the senior NFL writer for ESPN.com.