With the acquisition of Sergei Gonchar from the Dallas Stars in exchange for Travis Moen, the Montreal Canadiens are now projected to spend $28.9 million on their defence corps—just $2.5 million less than is currently designated for the forwards. With the trade, Montreal parts with a contract that has one season of term remaining and acquires a contract that expires at the end of the season, freeing up cap space for 2015-16. The Canadiens are responsible for (34 of the 186 days in the regular seaon =) 18.3% of Moen's cap hit.
Rene Bourque was recently assigned to the Hamilton Bulldogs of the AHL, which allows Montreal to shed a portion (153 of 186 regular season days' worth of a $925 000 AHL savings) of his cap hit. His cap slice is faded in the chart as he is not currently on the 23-man NHL roster.
Data obtained from CapGeek's Daily Tracker.
A public Google spreadsheet containing this cap info and the charts these visualizations are based upon is available here.