Brownie85
Mes que un muppet!
Very highly doubt that Sarri will go against the owners, seeing as he's pretty much only just started. Even if he didn't want Lukaku, he'd most probably go along with what the owners/higher ups wanted. Last thing he'd want is to have friction with his bosses.If that's true then Sarri will just tell him he doesn't want Lukaku but the club are pushing it. Dybala will then just say he's not leaving and Sarri will ease him back into the team.
My guess is, if he's going down that route is to tell him that the situation is out of his hands, and whilst he'd like to keep everyone happy, sacrifices have to be made and there is no way he's going to be able to fit him into the current squad and it's in his best interests to seek out playing elsewhere. Absolves himself of the responsibility and keeps the management happy at the same time.