Simek suffered a lower-body injury early in Thursday's game in Chicago and will be re-evaluated back home. Erik Karlsson is also heading back to San Jose and Alexander Barabanov will not be available on Saturday, leaving the Sharks with just 16 skaters in Dallas.
Simek dressed as a seventh defenseman on Saturday but will be scratched in favour of Jeffrey Viel on Tuesday.
Gustafsson played in three straight games but will be replaced by Caleb Jones in the lineup on Tuesday.
Leonard suffered a lower-body injury vs. the Oilers on Tuesday and will not be in the lineup on Thursday. Jonathan Dahlen will draw back into the lineup to replace Leonard.
Copp was acquired from the Jets on Monday and will start on a line with Filip Chytil and Dryden Hunt. Copp has scored 13 goals with 22 assists (35 points) in 56 games this season.
