According to Mark Feinsand of MLB.com, the Phillies are among at least six teams interested in Donaldson, who hit .259 with 37 homers, and 94 RBI with the Braves last season. The 2015 AL MVP will be 34 when the 2020 season begins.

But if they can't land Donaldson, one name to keep an eye on is Moustakas, according to Jim Salisbury of NBC Philadelphia.

Moustakas slashed .254/.329/.516 with 35 homers and 87 RBI in 143 games in Milwaukee for the Brewers. Signing the 31-year old could make sense on a short-term deal, with top prospect Alec Bohm, waiting in the wings.

As Salisbury writes:

They also could look to add a third baseman this winter as they allow top prospect Alec Bohm more development time and consider a possible move to another position for him. Boras represents two top free-agent third basemen, Anthony Rendon and Mike Moustakas.

This would allow Bohm at least another season of seasoning at Triple-A Lehigh Valley to work on his defense, which might not be ready for the big league level.