The NFL Free Agency rules are a little murky, given the fact the NFL owners have withdrawn from the NFL Collective Bargaining Agreement, and the 2010 NFL season will not be affected by a salary cap.

However we can break it down like this. There are two kinds of free agents: restricted and unrestricted. For the 2010 season a restricted free agent is a player whose contract has expired, but who ahs only played in three, four, or five NFL seasons. An unrestricted free agent in 2010 would be any player who contract has expired and has played six or more NFL seasons.

For 2010 the signing period for Restricted Free Agents began on March 5, 2010 and ended on April 15, 2010. If the player signed his July 1st tender, and is an unrestricted Free agent the signing period is March 5, 2010 to July 22nd or the first day of that team’s training camp, whichever is first.

Restricted free agents are also players who have received a qualifying offer from their old teams, but can continue to negotiate with other teams until April 15th. If the RFA receives an offer from a new team, his old team has the right of first refusal to match the offer or allow the player to move on. http://www.saintsnews.net/2010/03/05/the-nfls-free-agency-faq/

So far in 2010 the Detroit Lions have been very aggressive in signing free agents to their roster. Lions General Manager Martin Mayhew has stated that he inherited a roster full of backup talent, and is working overtime to try and rectify that.

In 2010 the Detroit Lions have signed the following Free Agents:

• WR Nate Burleson-UFA-five year, 25 million dollar contract
• WR Brian Clark-UFA-one year contract
• DE Kyle Vanden Bosch-UFA-four year, 26 million dollar contract
• LB Landon Johnson-UFA-one year contract
• LB Ashlee Palmer-UFA-
• CB Jonathan Wade-UFA-one year contract
• CB Dante Wesley –UFA-two year contract
• CB Jahi Word-Daniels-UFA-signed reserve/Futures contract

They have also resigned free agents:

• TE Will Heller
• C Dylan Gandy
• DL Copeland Bryan
• DL Jared DeVries
• CB Kevin Hobbs
• CB DeAngelo Smith
• FS Ko Simpson

http://www.kffl.com/static/nfl/features/freeagents/fa.php?option=Signed+by+Team&y=2010 http://www.rotoworld.com/content/clubhouse_contracts.aspx?sport=NFL&majteam=DET

Without a doubt the worst free agent signing made by this tam was QB Scott Mitchell. Mitchell stepped in for an injured Dan Marino and the Miami Dolphins during the 1993 season. Entering 1994 he was a highly coveted free agent QB, and the Lions signed him to an 11 million dollar deal. http://bleacherreport.com/articles/132344-top-10-worst-nfl-free-agent-signings#page/11

Placed into an offense that featured RB Barry Sanders, Mitchell had to merely manage the game. However, in five seasons with the Lions he was mediocre at best. His best year was 1995, but he was always at his worst when the Lions made the playoffs. http://www.nfl.com/players/scottmitchell/profile?id=MIT766982