Free agency means different things to different people.

In the case of the Green Bay Packers, it doesn't mean sifting through options and targeting prizes as much as managing a system that requires every team to make critical decisions about its future.

In the case of cornerback Sam Shields and possibly center Evan Dietrich-Smith, it means getting ready to move into a new tax bracket.

The focus in NFL free agency typically lands on unrestricted free agents like Joe Flacco, Greg Jennings, Steven Jackson and Wes Welker, but when the NFL calendar year begins March 12, the Packers will be investing a solid chunk of change in at least four of their five restricted free agents.

To maintain the rights to a restricted free agent - anyone with three years of experience whose contract has expired - a team must submit one of three qualifying offers, each of which comes attached with a level of compensation a team must pay for signing one of these free agents.

In the case of Shields and Dietrich-Smith, the Packers will have to decide whether to use the top or middle tender offer.

The highest tender sets compensation at a first-round pick, the middle tender sets it at a second-round pick and the low tender sets it at the round in which the player was drafted. In any of the three cases, the original team has the right to match any offer made to its restricted free agent.

The difficult part for general manager Ted Thompson is that both Shields and Dietrich-Smith were not drafted, so if the low tender is placed on them, there would be no compensation awarded if the Packers didn't match the offer.