LAKE BUENA VISTA, Fla. — Right fielder Fernando Martinez returns to action Saturday as the Astros face the Atlanta Braves in a 12:05 p.m. Grapefruit League game at Champion Stadium. Martinez was dealing with back pain. He initially said he’d be activated Sunday. Astros first baseman Brett Wallace (neck) is also back in the lineup. Righthander Philip Humber (1-1, 1.29 ERA) takes the mound for the Astros (11-13-2). The former Rice standout is matched up against Braves righthander Julio Teheran (2-1, 1.35). Astros’ starters – Altuve 2B, Wallace 3B, Pena 1B, Carter LF, F. Martinez RF, Maxwell CF, Castro C, Gonzalez SS. Pitchers – R Ambriz, R Fields, R Cruz, [...]