"Our thoughts go out to Jose's family, friends and many teammates," Astros general manager Jeff Luhnow said in a statement.
Oz Ocampo, Houston's director of international, said in a statement Rosario was a "true student of the game."
"He will be remembered as a long, lanky-framed pitcher with tremendous ability, an outgoing personality and an ever-positive disposition," Ocampo said.
Rosario made 18 appearances in the Dominican Summer League and Gulf Coast League in 2015, posting a 4.40 ERA. He spent the bulk of his time as a reliever, making eight starts in those 18 appearances. He pitched 57.1 innings, striking out 51 batters and walking 22.