I think he is opting out because he (and his family) want out of Boston.
Maybe he doesn't have much hope in himself to earn a great contract after next season and would rather cash out of 34 mil next year to get 4 years 25mil elsewhere.
'Elsewhere' would more than likely require a s&t, which I would be more than happy with. Don't get me wrong, I would happily keep Hayward in a deal w/ a slightly smaller AAV, but if Hayward just wants out, at least there is a decent chance we aren't left empty handed.
Honestly, one of the worst scenarios for us was Hayward simply opting into the $34M this season. If this report is true, at least we will be able to figure out our options and have more future certainty.