My guess is the Sox don't pick up his option after this year, given both his direction and their direction. He signs with the Reds in the offseason for a 1 or 2 year deal to finish his career in his hometown.*
You heard it here first (no inside info just an educated guess at this point).
*Unless of course Frazier or Henry Rodriguez absolutely light it up this year, in which case perhaps Youkilis could play LF.