Chicago assigned Greentree, 25, to the American Hockey League’s Rockford IceHogs.
Greentree appeared in two games with the Flames last season but spent most of 2008-09 with the AHL’s Quad City Flames where he led the club with career highs in goals (39) and points (76) while appearing in 79 games. Greentree, who was on the roster of Calgary’s AHL affiliate in Abbotsford, B.C., at the time of the trade, is scoreless in four NHL games, two with the Flames and two with the Philadelphia Flyers in 2007-08.
The Victoria, B.C., native has 65 goals and 61 assists for 126 points and 148 penalty minutes in 159 AHL regular-season games in parts of three professional seasons with the Philadelphia Phantoms (2006-08) and Quad City (2008-09). Prior to turning pro, Greentree had 41 goals and 101 points in three seasons with the University of Alaska-Fairbanks.
Johnson, who didn't appear in either of Chicago's two games this season, had 3 goals and 5 assists in 38 games with the Hawks last season, his first as a member of the organization after signing as a free agent on July 15, 2008. The 26-year-old native of Nova Scotia has played in 184 NHL games with Columbus, the New York Islanders and Chicago, scoring 10 goals and adding 26 assists for 36 points with 156 PIM.