if you draft 5000 usable PA you don't have much use for AAA hitters so there's nothing to trade for. the loophole around it is to draft some cheap high PA hitters you have no intention of using, then send them down for AAA. costs a little money but it's worth it for 2 reasons. AAA hitters are better now, and it should be easier to trade for good AAA because many owners won't need them.