De Los Santos (knee) is expected to begin throwing bullpen sessions sometime next week, Matt Kawahara of the Houston Chronicle reports.
De Los Santos has been shut down from throwing since he suffered a right knee strain at the start of camp. It remains unknown how far away he is from pitching in Grapefruit League games, though the Astros will likely also have the 30-year-old reliever face live hitters before using him in a competitive setting.