Astros pitching prospect Mark Appel will open the 2015 season at Double-A Corpus Christi.
Jake Marisnick doubled twice and drove in a run as the Astros edged the Tigers 3-2 on Wednesday.
Dallas Keuchel pitched 5 2/3 innings of one-run ball Wednesday versus the Tigers.
Astros prospect Kyle Smith underwent Tommy John surgery recently, according to the Houston Chronicle's Jose de Jesus Ortiz.
Astros placed RHP Josh Fields on the 15-day disabled list, retroactive to March 27, with a right groin strain.
Astros place RHP Brad Peacock on the 15-day disabled list, retroactive to March 30, with a right hip injury.
Astros placed LHP Brett Oberholtzer on the 15-day disabled list, retroactive to March 31, with lat soreness.
Josh Fields (groin) indicated that he's close to returning from injury.
Astros designated OF Alex Presley for assignment.
Astros optioned 1B Jon Singleton to Triple-A Fresno.
Astros optioned OF L.J. Hoes to Triple-A Fresno.
Astros optioned LHP Kevin Chapman to Triple-A Oklahoma City.
Luke Gregerson has been named the Astros' closer.
Roberto Hernandez has been named the Astros' No. 5 starter.
Astros purchased the contract of LHP Joe Thatcher from Triple-A Fresno.