The striker collected the award after hitting three goals in three league games in September and netting the winner in a League Cup tie at Dundee.
The Northern Ireland international has continued where he left off last season, when he struck 27 goals, by netting nine times in 10 games so far this campaign.
Butcher said: "He is exceptional. He's a complete professional, almost the perfect striker for us. He's the principal point of our attack obviously and the first line of defence.
"He is just wonderful. You would never think he is top of the Premiership goalscoring charts, by some way as well. You would never think that by looking at him: he is the most laid back member of the squad possibly.
"He just gets on with his job, no frills. He hardly ever misses training and doesn't miss many games at all.
"He keeps being there all the time and he keeps being there in the box to convert the chances. We love him to bits here and we're really pleased for him. And it's fully deserved."
McKay has the chance to add to his goal tally when Inverness host Partick Thistle on Sunday.
Both sides are looking to bounce back from defeats - Inverness lost 4-0 at St Johnstone before the Maryhill side fell to a 1-0 defeat by Hibernian.
But the First Division champions have made their mark in an impressive start to the season and Butcher, who had a short coaching stint at Firhill in 2007, is full of praise for Alan Archibald's side.
"They have done very well," Butcher said. "I was at Partick Thistle for a few weeks under Jimmy Bone and I certainly enjoyed my time there.
"It's a lovely club. They are in the big time now and quite rightly so. But they are also gracing the Premiership with their style.
"They are passing the ball really well, they have good movement and they have got young, energetic players.
"Alan, as a player, was a good passer of the ball. He liked to get the ball down and pass it out and dribble with the ball sometimes as a centre-half. Not quite the best thing to do sometimes.
"But his philosophy is coming across well, his philosophy is to get the ball down and play it out from the back and his team are doing it really well."