Why would the AFLPA have a field day.
Players often don't get where they want.
Are they going to complain about Papley & Daniher too?
He's uncontracted, has provided GC with 6 seasons of service and played almost 100 games.
If GC try to hold him there against his will, AFLPA will get involved. They are already agitating for free agency to be brought in sooner and this is a perfect scenario to sell that argument. AFL want to avoid this shit fight.
IMO the only way Martin stays at GC is if they agree to terms of a new contract before any draft, no way GC would be stupid enough or allowed to take him in PSD.