And yes, it's absolutely a risk. But that's

a) why you can get him cheaper with draft considerations coming your way as well. He'll be a lot cheaper than beloved players that every team wants and if you want to get value in a trade, you have to be willing to deal with certain negative perceptions - able to zig when everyone else zags.

b) probably an acceptable risk, given that the best alternative is "blow up the team and hope to get lucky in the lottery". If Simmons is a head case and out of the NBA and contributes nothing... well then you can still blow up the team and hope to get lucky in the lottery after that.

Plus, as mentioned (if we ignore his head-case issues) he's a REALLY good fit for the Jazz. Though he does necessitate additional moves to get a big who shoots well.