CHICAGO — Astros top prospect George Springer will soon be playing alongside Jonathan Singleton and Jarred Cosart. Righthanded pitcher Jake Buchanan and Springer were promoted to Class AAA Oklahoma City on Sunday, according to Class AA Corpus Christi. The Astros have not officially announced the moves. Springer, 23, was batting .297 with 19 home runs, 55 RBIs and a .979 OPS with the Hooks. Buchanan, 23, was 7-2 with a 2.09 ERA with Corpus Christi. The eighth-round selection of the 2010 MLB amateur draft has been one of the Astros’ best minor-league pitchers this season. Springer and Buchanan will join Jonathan Villar, Cosart and Singleton in Oklahoma City. Twitter: ChronAstros