Buchanan will be available for Friday night's game against the White Sox. This will be Buchanan's second stint with the Astros this season. The 24-year old right-hander is 1-1 with the Astros and has allowed five runs in 5 1-3 innings.
The Astros optioned right-hander reliever David Martinez to Oklahoma City. Martinez allowed four runs in seven innings of relief duty.