Trades among NFL team may happen form the beginning of a new League year, which is generally sometime after the NFL Super Bowl, and the official NFL trade deadline. This is usually in the middle of a NFL season. http://www.ehow.com/facts_4815748_official-nfl-roster-rules.html

Unlike Major League Baseball, NFL teams are allowed to trade their allotment of draft picks each year.

A few important things to remember is that most NFL trades happen during the NFL draft or in the summer as teams start to build their rosters at their training camps. Player for player trades are more frequent now days than they have been, but generally speaking NFL team usually trade players for draft picks in future NFL drafts.

NFL teams generally do not make trades with team within their own division. The idea there being they do not want to help a divisional opponent get better, when they will have to play them twice a year.

No new rumors to report 4-2010

April 22, 2010 The Detroit Lions trade their 2010 draft picks (34th, 100th, and 214th overall) to the Minnesota Vikings for the 30th overall pick to draft RB Jahvid Best. They also picked up the 128th overall pick in the 2010 NFL Draft

April 19, 2010- In a three team deal the Lions send LB Ernie Simms to the Philadelphia Eagles in exachange for TE Tony Scheffler of the Denver Broncos and Denver's 2010 NFL Draft seventh round pick (220th overall). The Broncos get the fifth round pick of the Eagles (137th overall)

April 5, 2010- The Lions traded their 2010 Fifth Round draft pick (133rd overall) to the Seattle Seahawks for OG Rob Simms http://profootballtalk.nbcsports.com/2010/04/05/lions-acquire-rob-sims-in-trade-with-seahawks/

April 5, 2010- in a separate deal the Lions sent DE Robert Henderson to the Seattle Seahawks for their 2010 7th round selection (213th overall)

March 25, 2010- Traded a 2010 sixth round pick and a conditional 2011 7th round pick to the Atlanta Falcons for CB Chris Houston http://profootballtalk.nbcsports.com/2010/03/25/lions-squeezed-falcons-into-taking-less-for-chris-houston/

March 4, 2010- Traded 2010 4th round draft pick to the Cleveland Browns for DT Corey Williams

March 142010- Traded 2011 7th round drat pick to San Francisco 49ers for QB Shaun Hill http://profootballtalk.nbcsports.com/2010/03/14/49ers-trade-shaun-hill-to-lions/

• October 28, 2008- Traded WR Roy Williams to the Dallas Cowboys for their 2009 first round draft pick (20th overall), 2009 third round pick (82nd overall), 2009 Seventh Round draft pick, and the Cowboys 2010 seventh round pick. http://sports.espn.go.com/nfl/news/story?id=3643295

The Lions used the 20th overall pick on TE Brandon Pettigrew, and the 82nd overall pick on WR Derrick Williams. This move allowed the Lions to trade the first overall pick in the third round to the New York Jets http://www.examiner.com/examiner/x-19045-NFL-Draft-Examiner~y2009m7d31-2009-NFL-Draft-analysis-Detroit-Lions

• April 26, 2009- traded third round pick(65th overall) to the New York Jets for their third round pick (76th overall), fourth round pick (115th overall), and seventh round (228th overall). http://www.inquisitr.com/67470/2009-nfl-draft-one-year-later-detroit-lions/ The Lions used these picks on LB Deandre Levy and DT Sammie Lee Hill who both look to be starters in 2010.

• November 29, 1958- traded QB Bobby Layne to the Pittsburgh Steelers for QB Earl Morrall and two draft choices http://blog.detroitathletic.com/2009/11/29/the-shocking-trade-of-detroit-lions-legend-bobby-layne/

• 1950- traded DE Bob Mann and cash to the Chicago Bears for QB Bobby Layne