In late November, the Mets added Andres Gimenez, Jordan Humphreys, Ali Sanchez, and Thomas Szapucki to their 40-man roster in order to protect them from the Rule 5 Draft. The move protected them from being selected in the Rule 5 Draft, an annual draft that was instituted as a means to prevent teams from signing and stockpiling players in their minor league systems. For a fee ($100,000), a team may select a player that has been left exposed to the Rule 5 Draft.
In order to avoid exposing a player, a team must add to its 40-man roster players signed at age 18 or younger that have five seasons of minor league experience, or players that were signed at age 19 or beyond with four years of minor league experience.