The 26-year-old Latvian leads the goaltending charts after recording seven shutouts and posting a save percentage of 92.2 per cent, the same as Blaze's Brett Jaeger.
After Mustukovs kept out 44 of 46 shots at Coventry at the weekend, player-coach Simon emphasised how important his team's first-choice stopper will be during the Elite League title run-in.
"'Moose' has been tremendous for us, his numbers speak for themselves," said Simon.
"He is an unorthodox goalie but he stops the puck. He doesn't get emotional, he doesn't get excited – he just stays stays on an even keel which for a goalie is so important – to keep a level head."
Steelers dropped to third on Monday night after title rivals and 'sister' club Cardiff Devils thrashed Dundee Stars 6-1. Cardiff's 16th straight win moved them two points ahead of Steelers and to within one of leaders Belfast.
Cardiff arrive in Sheffield on Wednesday, January 12 for the first fixture between the two clubs since Devils owner Paul Ragan took over at the Steelers shortly before Christmas.
The rivals also face a double header on February 19-20.
Nottingham Panthers moved to within three points of the Steelers - who have played one game less - after thumping bottom club newcastle Vipers 11-4 in Whitley Bay.