Per Jim Peyton at PhuturePhillies, the Phils appear to have only seven players at risk in the AAA (minor-league) portion of the Rule 5 draft:
Catcher:
Nerluis Martinez
Infielders:
Ali Castillo (recently signed)
Harold Garcia (DNP in 2018, but coached)
Kyle Martin
Emmanuel Marrero
Edwin Rodriguez
Drew Stankiewicz
I don't know anything about Castillo, but I don't expect any of the other six to have a major-league career; at most, a cuppa.