For the first time since the Orioles’ grueling rebuild began, the vibes entering a season were high. That balloon — one that grew ever-larger with talk about the end of the rebuild and postseason aspirations — was significantly deflated Monday afternoon when the team announced that prized pitching prospect Grayson Rodriguez would not make the opening day roster. The six weeks of spring training leading up to the controversial decision were drama-free, but the choice to start Rodriguez, a consensus top-10 prospect, in Triple-A ended that streak.