Ladd, 24, made $1.6 million playing for the Blackhawks last season, but he was part of a cost-cutting offseason by general manager Stan Bowman.
The left winger joins former Blackhawks forward Ben Eager as Thrashers players to avoid arbitration.
Eager agreed to a one-year deal worth $965,000.
Ladd scored 17 goals and had 21 assists while helping lead the Blackhawks to the Stanley Cup. He also won a Stanley Cup while with the Carolina Hurricanes in 2006.
Jesse Rogers covers the Blackhawks for ESPNChicago.com and ESPN 1000. The Associated Press contributed information to this report.