Sources told ESPN and the Detroit Free Press on Tuesday that the Lions have started the trade talks. Sources also informed NFL Network last week that the team-to-team discussions would begin in the coming weeks.
Stafford, 32, has two years and $43 million remaining on his contract, which makes it unlikely for the Lions to release the 2014 Pro Bowl selection and 2011 Comeback Player of the Year.
The Lions timeline to find a trade partner or release Stafford likely ends on March 21, as he is owed a $10 million roster bonus on the fifth day of the new NFL league year.
Stafford -- the No. 1 overall pick in the 2009 NFL Draft -- completed 64.2% of his throws for 4,084 yards, 26 scores and 10 interceptions in 16 starts this season. He reached the playoffs three times over his 12-year tenure in Detroit, but never won a postseason game.
Stafford's wife, Kelly Stafford, posted a goodbye message to Detroit earlier this week on Instagram.
"Whenever I figure out what the future holds, you'll be hearing from me again with a thank you that hopefully shows how much gratitude and love I have for this place, but until then we are going to enjoy our time left in Michigan to the fullest because there really is no other place like it," Kelly wrote.
Stafford will leave the Lions as the franchise leader in passing yards (45,109), touchdown passes (282) and interceptions (144). He had a 74-90-1 record as a starter for the Lions.