In addition to deciding on Tuesday which players to add to their MLB Reserve List (40-man roster) to protect them from being selected in the Rule 5 Draft, the Cubs also had to decide which Rule 5 Draft-eligible players to place on the 38-man AAA Iowa reserve list.
The 2018 MLB Rule 5 Draft will be held on the last day of the Winter Meetings (Thursday December 13th), and minor league reserve lists are used to determine eligibility for selection in the Rule 5 Draft. Once the reserve lists are filed, Rule 5 Draft eligible players on minor league reserve lists are essentially "frozen," meaning the player cannot be added to the MLB 40-man roster, transferred to a different minor league reserve list, or traded until the conclusion of the Rule 5 Draft.