Less than two days after he joined the Astros in a trade with new division foe Oakland, Travis Blackley landed on the 15-day disabled list on Saturday. To fill the vacant roster spot, Houston recalled pitcher Dallas Keuchel from Triple-A Oklahoma City. Keuchel, 25, posted a 3-8 record and 5.27 ERA in 16 starts for the Astros in 2012. He allowed eight runs (seven earned) on 16 hits in seven innings during Grapefruit League action this spring. The Astros acquired Blackley on Thursday. A day later, he suffered a left shoulder strain during a bullpen session at Minute Maid Park. His placement on the DL is retroactive to Friday