McKay suffered a minor tear to his meniscus, as well as bone bruising to his knee, during Saturday night's defeat to Collingwood.
The 28-year-old was ruled out early in the game after his knee knocked into teammate Sam Walsh.
But speculation around McKay ran rampant during the night, Fox Footy commentator David King leading the questioning of the one-time Coleman medallist's injury.
The Blues were privately seething with McKay's character being criticised, before the severity of the injury was confirmed on Sunday.
McKay didn't appear during Carlton's main training session on Thursday.
Fraser admitted he "didn't spend a lot of time thinking about" the commentary surrounding McKay.
"Whenever there's an injury, your mindset goes to the care and support for the player," he said.
"We act on the information we're given from our medical team, the commentary around all of that, I probably push it to the side.
"I can only judge him on the way he's presented and he's presented his usual self. Great energy around the group, trying as hard as he can to play and leading internally around the club."
Fraser hoped McKay's injury was on the "lower end", but meniscus tears, even minor ones, can still be painful and tricky to overcome.
Carlton's wildcard hopes will go on the line on Saturday when they host out-of-form Gold Coast at Marvel Stadium.
After winning their first seven games when Fraser took charge following Michael Voss' exit from the club, the Blues have dropped their last two matches to Hawthorn and the Magpies.
But the Suns - premiership favourites early in the season - are on a league-worst eight-game losing streak in a dramatic fall in recent months.
"Their best footy is really good," Fraser said of Gold Coast.
"They've got talent across the field.
"Their ability to open the game up through forward handball and moving the ball, they're a dangerous side, so we respect that."
Fraser continues to distance himself from the process to find Carlton's permanent senior coach, saying "nothing's changed for me".
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