"It just seems that young people, they do get a bit puffed at the end of the year, and we certainly have a couple of them," he said.
"That's experience to know when they are and just not leave them out there for the sake of it, because you can run into bad habits.
"Usually they'll take you off the rails when you haven't got the ball, they don't help too much in that area."
The coach confirmed Macrae would be recalled next week to face the Swans after the 20-year-old was withdrawn against the Roos with "wear and tear".
"[Macrae] has done a great job for almost two years and we thought he was at the end of his tether last week.
"He didn't see it that way but we did and that's the beauty of him, he's so competitive. He'll come back in next week and finish the year really strong."
One player who McCartney said was "roaring on" was the Bulldogs' fourth pick in last year's draft, Marcus Bontempelli.
The favourite to win the NAB AFL Rising Star award sparked a Bulldogs' revival in the second term against North Melbourne, and after attracting close attention from the opposition in the third quarter, rebounded well in the final term to finish with 23 disposals, eight tackles and two goals.
"[Bontempelli is] a young player who isn't ready to do it for a full four quarters yet, but it doesn't look like he's too far off, does it?" McCartney said.
"He's a good young boy, so balanced and leveled too. He's got a really good understanding of the game, and what to do. It's a lot easier to coach boys like that.
"We looked after him really well at the start, he didn't play a lot of footy, do a lot of training and that's how we do things with young boys in their first year."
Fatigue will have to take a back seat though for the Bulldogs next week as they face the Sydney Swans at Etihad Stadium in round 22.
McCartney said he hoped the players would arrive at training on Tuesday with "a spring in their step".
Out-of-contract Bulldog Shaun Higgins left the field in the final term against the Kangaroos after he suffered a knock to the head, with McCartney unsure of his availability for the game against the Swans.