They were able to trade it once it became officially theirs. You can't trade a 1st rounder when you owe two future 1sts, but if you own the first for that year, you can trade it. Edit-I don't know that this made sense. Point is, they can trade it. They couldn't trade it before it was officially theirs for this year. It's to protect teams from themselves. That is just overly confusing dang you NBA and your weird rules!