Morey may very well be having conversations with teams now along the lines of "we can't swing a trade for Simmons now, but if you can hold out until December 15 we'd gladly trade [Player X] for him." If so, Morey has to weigh whether two months where Simmons' roster spot is just nonexistent is worth whatever potentially improved offers he may get later in the season. Once you factor in that there is a non-zero chance that Simmons buckles and ultimately does return to the team for some portion of that two-month-ish span (even if he's surly and underperforming), I can definitely see a world where Morey does nothing until December.