Simmons can try to exert what leverage he has to go where he wants, but unfortunately for him, NBA rules are pretty ironclad. He'd have to sit out the entire season and then re-enter the draft...and hope that that time around the Lakers are able to get him. And of course by sitting out a full year, he would delay his contract clock, so he'd be pushing back FA and all the "service time" aspects of the cap rules (i.e. the rules that allow longer tenured players to get a larger max deal) back. He'd also be entering a far more loaded draft class, so while the Lakers might have a better shot at him, he'd also make less money as he'd be far less likely to go #1 or #2 in that stacked class. There's just no way that Simmons isn't signing with whoever drafts him, just like no NBA player under the modern draft rules has done (nor any NFL draftee since their rules were changed).