Harvey will play his first game of the season at Etihad Stadium in Saturday's twilight match after serving a six-match suspension incurred in last year's finals series.
Scott said the Kangaroos routinely decide on their substitute at the last minute but considers Harvey an option for the role.
"I think it'd be a nightmare for the opposition coach," he said at Aegis Park on Friday.
"If it were me in an opposition coach's shoes, I'd be worried about when he's going to come on and what we do about it ...
"I said last week we wouldn't do it because we wouldn't allow it but (even) in his 347th game he's still got to do what he's told. We'll do the best thing by the team there, and he's more than willing to do the best thing for us to win...
"'Boomer' has been saying for a long time that he'd be a perfect sub, but he's not prepared to do it until he's about 38 or 39."
Scott said Harvey had a history of performing well in his first game after an absence.
"Coming back from suspension is very different obviously to coming back from injury. He's trained very well, he's fitter than he's ever been, he's just a remarkable athlete and we expect him to come in and do what he's done over a long period of time," he said.
Scott also believes that when Harvey finally retires "as a 350, 400-game-plus player" he should consider pursuing a coaching career because "he has a hell of a lot to offer the game of AFL footy".
"I've been really impressed with him the last two or three years in playing a mentoring role for our young players," he said.
"He's got a unique football brain and he really understands the game, and sees things from a different perspective than I do at times, which is really healthy and it's helped broaden my horizons as well ... I think it'd be a shame to lose him to the game."
Despite being 2-4, Scott believes the Roos are playing "some of the best footy" they have produced in his four years as coach. Lapses in concentration had cost them, he said.
They are widely expected to win well against the 1-5 Bulldogs, but Scott isn't taking anything for granted.
"They could easily start their midfield with Boyd, Cross, Griffen, Cooney, Liberatore, Giansiracusa … You look at their team on paper and I'm little bit staggered that they don't have a lot more wins to their name," he said.
