For fun, I'm consolidating TalkNats, Camerato, and Next Gen speculation about 40 man roster adds below. I'm not going to deal much with cuts to make room for minor leaguers because the choices are almost unlimited. Dom and Robles are the biggest non-tender decisions.
TalkNats - lock is Herz, Powell in the mix, next tier Parker, Henry and Lara.
Camerato - discusses the MLB top 30 who are not on the 40 man but need to be added or exposed: Made, Henry, Lara, Parker, Brzykcy. Missed Herz.
Nextgen - Herz a "slam dunk." Henry and Brzykcy likely, then Parker / Cate, with NextGen leaning towards Parker. Also IDs Powell and Cluff as other potential keeps, with Cluff mentioned primarily because the author thinks the front offices see something in him no one else does.
Taking a consolidated view, we can give Camerato a break for not mentioning Herz and deem him a lock.
Henry also seems likely.
I don't like Camerato's approach to focusing just on the top 30 because some like Made are too far away from the majors to be kept on a roster all year. Lara is young, but he's not made it past A+, hasn't dominated any level yet, and velo was down. I think he's a difficult stash on a roster next year so I don't think he is added.
There's decisions to be made on Parker, Powell, Brzykcy. I expect Parker to be kept because, after Herz, the organizational starter depth looks thin. he's a lefty too, and lefties get breaks. Powell is a wild thing with an injury history. I think he's not given a spot despite being pushed up to AAA. Bombing out in the fall league. I buy the case for Brzykcy based on the easy stash, so he's an add.
Nats are at 41 players between rostered guys and 60 day IL guys who must be added or released. Figure there's a need for 4-6 roster spots. I think NextGen has it about right, with 4 adds, meaning 5 cuts.
Likelies to be removed from the 40 man would be De La Rosa, Call, probably Abbott, then go from there. Cronin probably doesn't need a spot with his injury coupled with a lack of a demonstrable recovery last year. I forget what the diagnosis was on his injury. Maybe Dom and Robles, maybe one of Alu or Downs. If Call is cut, then Robles could stick around as the starter and Young as the depth piece.
I do not think Machado is dropped. Pineda might be a luxury at this point.