The Astros have designated pitcher Jake Buchanan for assignment in order to add relief pitcher Joe Thatcher, per the Houston Chronicle's Evan Drellich.
Jake Buchanan has been designated for assignment to make room on the 40-man roster for Joe Thatcher.
— Evan Drellich (@EvanDrellich) September 1, 2015
Buchanan has bounced between the Astros and Triple A Fresno (and Oklahoma City before that) for that past two season. He appeared in 22 games during his major league career, making two starts in 2014. This season, he has mostly been used as a long man -- allowing two runs on five hits over nine innings.