Castillo, 29, is hitting .254 with 12 home runs and 40 RBIs in 80 games for the D-backs this season. He is awaiting the birth of his second child.
Hernandez is hitting a combined .255 with 10 homers and 31 RBIs in 61 games split between Class A Visalia and Mobile in 2016. The 23-year-old made his Major League debut in 2015 with Arizona and appeared in 18 games.
Oliver Macklin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.