Carlton could leave him rot in the VFL if they want, but doing that won't get them fair compo next year, in fact it will only hurt their claims as the AFL aren't going to give an end of first round or second round pick to them for a guy who spent the year in the VFL. So Carlton could call Yarrans bluff and not trade him, but do they really want a player around who doesn't want to be there, especially with a new coach who is trying to instill a new brand of discipline.
So what does Carlton do? Well pick 12 is too high for Yarran, even if it drops down to pick 17 with academy picks and compo picks. Pick 35 is too low a price for him, which means somewhere in between for him. We don't have a pick in that range so that means a player. The player that I believe would be best suited to Carltons needs would be McBean, a 199cm 94kg KPF who has kicked 30-40 goals a season in each of his 3 VFL seasons.
With Carlton not getting the extra pick for Kreuzer leaving, they could do worse than ask for McBean straight swap for Yarran and together with Weitering they would have their KPP bookends sorted for the next decade. With the pick they get from Geelong for Henderson, and their second round pick, they could add some decent young midfielders to go with Cripps. If Bell leaves they could take a crack at getting Aish as well and really set themselves up.
Then again Carlton could play hardball like their fans want and miss out altogether on making the best of the situation.