You're over-valuing them. IF Arthur is more athletic than Millsap, what else does he do better than him? That's rhetorical, there isn't anything. AND the Grizzlies were in trade talks involving OJ Mayo from just about the tip-off of the season to past the trade deadline where he WAS traded for Josh McRoberts (and maybe a pick) but it got done too late and couldn't be approved. That's beside that Mayo isn't athletic at all, isn't long, strong, and hasn't gotten any better since his rookie year (he's actually gotten worse).WHY? Do you see how good Memphis is doing? Why would they dump Mayo, who is still young and has major potential for that? A 12th pick is a huge gamble. Arthur is still young, and is far more athletic than Millsap. That is trading their core. You're out of your protocol.
OJ Mayo and Darrell Arthur are nice players, but they are not the Grizzlies core.