Here's the Rule 5 list:
Rivaldo Avila
Angel Bastardo - maybe
Brock Bell
Royman Blanco
Brainer Bonaci - maybe
Zach Bryant
Maceo Campbell
Allan Castro - maybe
Brendan Cellucci
Felix Cepeda
Juan Chacon
Casey Cobb
Nathanael Cruz
Luis De La Rosa
Nick Decker
Kelvin Diaz
Jordan DiValerio
Shane Drohan - maybe
Juan Daniel Encarnación
Alex Erro
Albert Feliz
Ryan Fernandez - maybe
Ryan Fitzgerald
Grant Gambrell - maybe
Jhostynxon Garcia
Wikelman Gonzalez - maybe
Bryan Gonzalez
Justin Hagenman - maybe
Alexis Hernandez
Gabriel Jackson
Lyonell James
Gilberto Jimenez
Christian Koss
Robert Kwiatkowski
Chih-Jung Liu - maybe
Eduardo Lopez
Matthew Lugo
Elih Marrero
Yorberto Mejicano
Ryan Miller
Andrés Núñez
Yusniel Padron-Artiles
Eddinson Paulino
Luis Perales - maybe
Railin Perez
AJ Politi
Jose Ramirez
Oscar Rangel
Jorge Rodriguez
Ronald Rosario
Cesar Ruiz
Johnfrank Salazar
Stephen Scott - maybe
Cody Scroggins
Reidis Sena
Chase Shugart
Karson Simas
Nick Sogard
Noah Song
Dylan Spacke
Joey Stock
Luis Talavera
Nate Tellier
Michael Valera
Brian Van Belle
Diego Viloria
Jeremy Wu-Yelland
Ryan Zeferjahn
That's 11 guys they have to consider protecting and they won't put all of them on the 40 man roster. That's why there's a risk they'll lose a few guys to the Rule 5 draft. They can't stash a bunch of guys on the 40 man roster that they won't have any intention of using. They can probably stash 3-4 at most. The current 40 man includes Mata, Rafaela, Abreu and Hamilton, but they were reluctant to use any of them this season. Would they be willing to stash Castro for 2 years? If Bonaci is added, will they actually use his 40 man spot and call him up for his defense? Is Scott's defense good enough to be the 3rd catcher in this org? I could see an outside organization taking those 3 guys in Rule 5 if the Sox don't protect them.