General manager Jeff Luhnow dipped back into his baseball roots, claiming infielder Ryan Jackson off waivers from the St. Louis Cardinals. The Astros also outrighted outfielder J.D. Martinez to Class AAA Oklahoma City and released righthander John Ely and lost infielder Jake Elmore after he was claimed off waivers by the White Sox. Jackson, 24, is the latest former Cardinal to land in Houston since Luhnow left St. Louis to take over as the Astros’ general manager. The former University of Miami fifth-rounder from the 2009 draft spent most of last season at Class AAA Memphis, hitting .278 with 34 RBIs. Much like Elmore, Jackson is a versatile infielder who logged in significant time at shortstop, third base, second and the outfield last season at Memphis. Elmore, who became the first Astro to play every position in a single season while making two stints with the major league club, made franchise history against the Rangers when he caught and also pitched in the same game after Max Stassi was injured. Elmore, 26, played 52 games and hit .242 with two home runs and six RBIs.