The bereavement list can be used when there is an illness as there is in this case.
By Friday night there was good news about the newborn.
"He is finally out of danger," Castillo posted on his Instagram page. "Our family is hoping we can get him home soon."
Catcher Oscar Hernandez, who joined the team Tuesday when Castillo was placed on the paternity list, will remain with the team.
Steve Gilbert has covered the D-backs for MLB.com since 2001. Follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.