MINNEAPOLIS – Brett Oberholtzer got the call Friday. Saturday was Brad Peacock’s turn. The 25-year-old righthander is expected to be called up from Class AAA Oklahoma City and scheduled to take the mound against the Twins during a Sunday series finale. Peacock made the Astros’ opening-day roster but allowed 26 hits, 20 runs and 13 walks during his initial five games. A May 2 demotion to OKC followed, as did a brief 12-day return to the majors that bridged late May with early June. This time, Peacock could stick. The Astros’ rotation remains unsettled, with three starters either scratched or pushed back this week due to the non-waiver trade deadline [...]