You can’t draft someone in this draft who hasn’t played in AAA. Prospects will be available in the last June draft we have this year, and then in the annual February NPD
But more to the point, there isn’t really a distinction between the two types anymore. You have 25 MLB slots, and 14 MiLB slots, and can freely move players between the two rosters as long as they have a green flag (which Fantrax assigns if they’re not on an MLB roster in real life).
The only restriction is that you can’t have anyone exceeding 1000 PA or 50(GS + 0.5*relief appearances) in your farm at the start of the annual NPD that will occur every February.