This Chron article lists some of the guys who'll be participating in instructional league, including Hector Perez, JJ Matijevic, and Corbin Martin. Near the end it also drops in this tidbit that I hadn't heard:
"Also of note among those participating is 19-year-old righthander
Lupe Chavez, who has returned from his brief retirement. Chavez, the low-level pitcher the Astros acquired in 2016 for Scott Feldman, retired suddenly in April for reasons undisclosed."
