Sewald (oblique) will throw a second bullpen session Tuesday, Theo Mackie of The Arizona Republic reports.
Sewald threw 18 pitches in his bullpen session Saturday, which was his first since being placed on the 15-day IL with a Grade 2 left oblique strain. It's unclear what the next step will be after Tuesday's session, but Sewald will presumably eventually advance to throwing live batting practice before heading out on a rehab assignment.