In 133 career NHL regular-season games with the Los Angeles Kings and Hurricanes, Westgarth has accumulated three goals and six assists for nine points, along with 202 penalty minutes.
The native of Amherstburg, Ontario, joined the Kings organization on March 17, 2007 as a free agent. He won a Stanley Cup with the Kings in 2010-11.
Nemisz, 23, has played in 15 career NHL games with the Flames, registering one assist and seven shots.
The antive of Courtice, Ontario, was originally drafted 25th overall by the Flames in the 2008 NHL Entry Draft.
In 32 games with the Abbotsford Heat of the AHL so far this season, Nemisz has tallied five goals and four assists for nine points.