That was speculation by Acres manager Colin Young who will likely be the one trying to broker a deal between Freo and Carlton for Acres. He's the one who states the 3rd round pick should be fair so the source is the person negotiating the deal for Acres. He has a bias of wanting the trade to happen.
If Carlton finish 8th next season which is every chance given their progress and the age of their list, the best we could hope for is pick 47. That would be dropped for each father/son or academy player selected before it of which there are often at least half a dozen by that point to be conservative. So a pick in the 50's, if not later is what we are dealing with here.
A player taken at that point in the draft is purely speculative and not likely to amount to much, a far cry from a player who was on target for All Australian in his position this season and still has 4/5yrs of good footy left. There are teams who would absolutely grab him in the pre-season draft ahead of Carlton (that would like him, have the salary cap room and fulfill the Melbourne based requirement) so the threat of walking him and not completing a deal is more of a risk to Carlton.
If they want Acres which they've shown they do by offering more than us for his services with a sizeable contract, they should pay for him. Their second round pick is currently 28 which will drop a number of spots after f/s and academy picks, we'll take that as a minimum.