Over at Baseball America, they have a list of the ten youngest players in each full-season league. Where do we find the Astros?
Jose Altuve is the youngest player in Major League Baseball (and only four days younger than Seattle's Erasmo Ramirez).
Jordan Lyles is the 3rd-youngest player in the Pacific Coast League.
Jonathan Singleton & Jonathan Villar are the 3rd and 4th youngest players in the Texas League.
Enrique Hernandez is the 8th-youngest player in the California League.