July 18, 2017 Derek O'Hara Derek O'Hara, Minor League, Scouting Report David Martinez: RHS, Houston Astros (AAA) July 18, 2017 Derek O'Hara Derek O'Hara, Minor League, Scouting Report David Martinez is a 29 year old AAA starter in the Houston Astros. Martinez reminds me so thoroughly of Christian Bergman in his loose/easy arm action, delivery and approach only Martinez has a better arm to boot.