Sosa was 2-0 with a 5.12 ERA in six starts at Triple-A Oklahoma City this season. The 26-year-old is out of options and could become a Minor League free agent at the end of the season if he's not on the 40-man roster.
The Astros acquired Sosa and relief pitcher Jason Stoffel from the Giants in exchange for infielder Jeff Keppinger prior to last year's Trade Deadline. Sosa went 3-5 with a 5.23 ERA in 10 starts for the Astros last year, allowing 54 hits and 23 walks while striking out 38 batters in 53 1/3 innings.
Stoffel, 23 has shown some promise. He's 0-1 with a 1.59 ERA and 17 strikeouts in 17 innings pitched at Double-A Corpus Christi.