The Braves payroll was $112M only so they could sign Santana. I would fully expect the payroll to be right around $100M for 2015, and probably under $100M.
There is simply no way on Earth we see Miller in a Braves uniform in 2015.
I would expect Hart/Coppy to be shopping in that middle tier of SPs that will cost less than $10M per year, and then filling out the bench and platoon partners via trades.
No way should a team with a terrible offense and significant payroll constraints be trading away a guy that can post an .800+ OPS while making $600k. It would be incompetent and border on lunacy.
Again, I'm not saying we "will" or "should" sign him. Just pointing out that it's not something that can't happen.
To be honest, now that Cespedes has signed with Jay-Z, I fully expect Boston to press hard for Heyward this winter if they can move him. If I'm Hart I'm telling them not to call back until Betts is in the deal.