19 Cubs minor leaguers were declared MLB Rule 55 minor league free-agents Monday afternoon:
11/7 UPDATE: RHP Jose Rosario has indeed been added to the Cubs MLB Reserve List (40-man roster).
Also, RHP Andury Acevedo, RHP Dallas Beeler, and C Tim Federowicz have been sent outright to AAA Iowa.
Acevedo will be declared an MLB Rule 55 minor league 6YFA if he does not sign a 2017 minor league successor contract, and Federowicz has the right to elect to be an Article XX-D minor league free-agent (because he has been outrighted previously in his career), but even if he doesn't elect free-agency per Article XX-D he will be declared an MLB Rule 55 6YFA if he does not sign a 2017 minor league successor contract.
Beeler does not have the right to elect free-agency if outrighted and he is not eligible to be an MLB Rule 55 minor league 6YFA post-2016 either, so he will remain under club control through the 2017 season, although he is eligible for selection in next month's MLB Rule 5 Draft. However, since he wasn't claimed off waivers ($20,000 waiver claiming price with no roster restrictions), it is very unlikely that he will be selected in the Rule 5 Draft ($50,000 draft price plus roster restrictions);
Post-2016 MLB Rule 55 minor league 6YFA and second-contract free-agents who decline to sign 2017 minor league successor contracts are now being added to MLB 40-man rosters in advance of next week's deadline, as the Cincinnati Reds have added RHRP Ariel Hernandez and the Texas Rangers have added OF Drew Robinson to their respective MLB Reserve Lists.
Usually no more than a dozen potential minor league free-agents are added to MLB 40-man rosters each year. As far as potential Cubs minor league free-agents are concerned, I would expect the Cubs to add RHRP Jose Rosario to the 40 by next Monday's 5 PM (Eastern) deadline, unless he agrees to sign a 2017 minor league successor contract.
A minor league successor contract is essentially an agreement between the player and the club to extend club control for one more season, usually with a financial inducement for the player (and sometimes an NRI to Spring Training as well). However, a potential post-2016 Rule 55 minor league free-agent who signs a 2017 minor league successor contract prior to Monday's deadline becomes eligible for selection in next month's MLB Rule 5 Draft, as does any free-agent who signs a 2017 minor league contract prior to the Rule 5 Draft, so the only way the club can be sure to retain the player is by adding him to the 40.
For example, LHRP Jack Leathersich (previously non-tendered by CHC) was eligible to be a Rule 55 second-contract minor league free-agent post-2016, but he signed a 2017 minor league successor contract with the Cubs in September. However, he will be eligible for selection in next month's Rule 5 Draft if he is not added to the Cubs MLB 40-man roster pror to the deadline for submitting MLB and minor league reserve lists to the MLB Commissioner on 11/18. NOTE: The roster filing deadline usually is 11/20, but it is moved up two days this year because the 20th falls on a Sunday.