The AI never propose trade

[Gary Gorski]

It may just be that the AI does not want those players - you have to put something on the block they a) want and b) can trade for. If you put a decent player on the block but he has a horrible contract the AI is smart enough to know that's not something they should trade for

[ripkobe]

Having multiple options on the block helps too. You might not WANT to trade someone, but might have to to get rid of someone else - as often is the case in the NBA.