The move for Mashinter is retroactive to last Wednesday. It looks as if Chicago will have a roster of 13 forwards, eight defensemen and two goaltenders for Thursday's regular-season opener at Dallas.
The Blackhawks did not identify Mashinter's injury in Tuesday's release. The 26-year-old Mashinter appeared in three preseason games with Chicago and recorded one fighting major.
Mashinter was acquired in a trade with the New York Rangers on Dec. 6, 2013. He has appeared in 23 NHL games.