The Astros placed recently acquired lefthanded pitcher Travis Blackley on the 15-day disabled list Saturday. Blackley joined the Astros on Friday via a trade with Oakland. The 30-year-old strained his left shoulder during a bullpen warmup session at Minute Maid Park. Blackley’s DL stint is retroactive to Friday. To replace Blackley, the Astros recalled LHP Dallas Keuchel from Class AAA Oklahoma City. Keuchel, who made 16 starts for the Astros in 2012, is scheduled to join the team in time for a 6:10 p.m. game Saturday against the Athletics. Keuchel, 25, posted a 9.00 ERA in seven spring training innings and recorded a 5.27 ERA last season. Twitter: ChronAstros