The 23-year old Barker, who is the in the middle of the first year of his three-year, $9.25 million contract has recorded 4 goals and 10 assists in 51 games this season.
Barker, was one of the five players in Chicago whose qualifying offers did not arrive on time last summer. That led to a grievance being filed by the NHL Player's Association.
The result was that the Hawks gave Barker a more significant raise then they had to, if the qualifying offers were handled properly.
Since the Blackhawks already have Marian Hossa, Jonathan Toews, Patrick Kane, Duncan Keith and Brian Campbell signed to big money, long-term deals, dealing away their commitment to Barker makes financial sense.
Johnsson, who has six goals and eight assists in 52 games this season is scheduled to become an unrestricted free agent at the end of the season.
Leddy has played 19 games with the University of Minnesota, posting 1 goal with 4 assists and 4 penalty minutes.