It's an unpopular stance, but I think AA needs to tell Donaldson "here's as far as we're interested in going, and you've got 24 hours to accept". There are simply too many teams involved, and the others can afford the 4th year or higher AAV much easier - unless there's lots more to this apparently increased payroll flexibility than any of us have even dreamed at this point.
Unless AT LEAST two of Newk, Wright, Wilson, or Anderson takes that significant step forward, you're looking at needing a minimum of $30-$35 million to fill the Hamels/Folty rotation spots in 2021. Hopefully AA will be in a position to replace Flowers, Markakis, and Duvall from within, but the money saved there PLUS getting Melancon and Greene off the books doesn't necessarily cover the two rotation spots. Folty, Soroka, Fried, Dansby, Newk, O'Day, and Jackson are all going to be due pretty significant raises. Even if the $150-$160 million level is the new "normal", Acuna is due a $4 million raise following this season and jumps another $10 million at the same time you have to make a decision on Freeman, AND there are no guarantees AA's going to be able to just wave his hand and make Ender's money go away next winter.
It's great that the idea that we're truly in on Donaldson is out there since it hopefully drives the price up for everyone else, but unless he's willing to take significantly less than where it looks like this is headed he's not coming back - and if he was, he'd already have signed by now after seeing the pen improvements and Hamels addition.