Senior assistant coach Justin Leppitsch took training at the AIA Centre on Wednesday as McRae rested at home.
"He's just a little unwell," Leppitsch said.
"It's not bad. You just figure stay away, obviously things can get contagious, potentially, so nothing that's going to stop him from being there this weekend.
"He'll be fine by the time we get on the plane."
High-flying Collingwood will face lowly West Coast at Optus Stadium on Saturday in an ultimate AFL mismatch.
The premiership favourite Magpies are on a seven-game winning streak to be a game and significant percentage clear on top of the ladder.
West Coast have been battered by injuries and are struggling badly for a second-straight season, sitting last with a 1-10 record.
Leppitsch confirmed star veteran Steele Sidebottom would miss up to eight weeks after injuring his knee in his milestone 300th game on Sunday.
The club initially hoped Sidebottom would only miss a month, but the Magpies will take a cautious approach with their 2010 premiership hero.
"The positive is he's back at the right time of the season for us to be fresh and get the body ready," Leppitsch said.
Electric forward Jamie Elliott has been ruled out of this week's match against the Eagles due to a shoulder injury.
"It's not too bad at all (Elliott's shoulder), he's been managing it for about a month, but given the six-day break and the travel and hadn't pulled up as well as it previously had, we decided that this is the week probably best not to play," Leppitsch said.
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