This years. Then 4 after the Stewart stuff. 28, 29, 30, and 31.
So they could do 25, 28, 30 or 25, 29, 31.
Any year not listed can also be traded. Easiest way is via a pick swap with the team they are trading with. Those are less valuable because we receive their #1 back.
So basically 3 outright and more via pick swaps.