The 24-year-old outfielder had 37 homers and 108 RBIs with 45 stolen bases combined in Double-A and Triple-A last year. He was off to a strong start in Triple-A this season, too, hitting .353 with three homers and nine RBIs.
Springer told The Associated Press he received the news after Oklahoma City's win over Colorado Springs on Tuesday night, when he hit a grand slam.
''It's just an indescribable feeling,'' Springer told the AP. ''I'm speechless right now.''
The Astros officially announced the move Wednesday and sent outfielder Robbie Grossman to Oklahoma City to make room for Springer on the roster. Grossman was hitting just .125 in 14 games this season. The team also reinstated starter Scott Feldman, who will start on Thursday, from the bereavement list and designated right-handed pitcher Lucas Harrell for assignment.
Harrell allowed four runs in five innings of a 4-2 loss to Kansas City on Tuesday night to drop his eighth straight decision dating back to last season and has not won a start since June 15. He led the American League last season with 17 losses.
Springer was selected 11th overall by the Astros out of UConn in the 2011 amateur draft.
Oklahoma City interim manager Tom Lawless called Springer into his office after Tuesday night's game and told him he'd want to sit down for the news. Springer said he just put his head in his hands because he was so excited and surprised when he found out about his call-up. Despite his big start this season, Springer said he had no inkling that his call-up was coming.
''As a player, that's your ultimate goal and that's your dream,'' Springer said, ''and when it becomes a reality, you're blown away.''
Springer was in Colorado Springs, Colo., and wasn't sure of his travel plans yet. But he said he was told he'd be heading to Houston at some point on Wednesday.
''I'm really excited that my hard work has paid off and I'm finally getting to fulfill my dream of playing in the big leagues,'' he said. ''I'm looking forward to playing for the Astros.''
He said his parents were the first people he called after learning the news and they, too, were speechless.
''They were just in shock and so happy,'' he said.