Westgarth, who turns 30 on Feb. 7, had no points and four penalty minutes in 12 games with Carolina this season. He has three goals and nine points in 133 NHL games during parts of five seasons with the Los Angeles Kings and the Hurricanes, who acquired him from L.A. before the 2012-13 season.
"I think through my career, at the risk of sounding immodest, I like to bring a physical presence and a lot of grit and a lot of work as well as hopefully some experience and leadership," the 6-foot-4, 233-pound forward told the Flames' website. “I look forward to giving everything I've got to the Calgary Flames and helping out in any way."
Nemisz, 23, was the Flames' first pick (No. 25) in the 2008 NHL Draft. He has spent all of the 2013-14 season with the Abbotsford Heat, the Flames' farm team in the American Hockey League, contributing five goals and nine points in 32 games. Nemisz has one assist in 15 NHL games during stints with the Flames in 2010-11 and '11-12.