As per TSN
Byfuglien, along with Brent Sopel, Ben Eager and Akim Aliu, will be headed to Atlanta in exchange for the 24th overall pick at the 2010 NHL Entry Draft, the 54th pick, Marty Reasoner and Jeremy Morin.
The 25-year-old forward had 17 goals and 17 assists in 82 games with the Hawks last season.
At 6'4, 257 pounds, the Minnesota native will bring his thunderous size and strength to the struggling Thrashers franchise.
Byfuglien was originally selected 245th overall by the Blackhawks in the eighth round of the 2003 NHL Entry Draft.