Houston designated Corporan for assignment on Tuesday to make room on the 40-man roster for free agent outfielder Colby Rasmus.
The 31-year-old Corporan hit .235 with six homers and 19 RBIs in 55 games for Houston last season. The Astros chose to part ways with him after trading for catcher Hank Conger and outfielder/catcher Evan Gattis.
The 19-year-old Bostick was a second-round pick by the Rangers in 2013. He is 9-7 with a 4.44 ERA in 35 appearances over two minor league seasons.