Never said they would trade him for Stroman. There's a reason why every time trading Bellinger is brought up by Cubs insiders they also mention the struggle in making that happen. They aren't going to get an offer of Clarke Schmidt for a $32M 2.5 fWAR player.
Saying that the Cubs aren't just going to dump his salary is just foolish, though. The rumor is the Cubs are wanting to trade him. It's not that he is available in trade, they WANT to trade him. They are telling you that they want out of his salary. Now, maybe things have changed since the tender deadline and they have just accepted the fact that there is no way out of his contract, thus the non-tender for Tauchman and they would need plan A in place before discussing Bellinger again, but that doesn't change their desire to get out from underneath that pile of wasted money.