Nelson (shoulder) is scheduled to throw a 25-pitch bullpen session Tuesday, Jesse Friedman of GoPHNX.com reports.
Nelson is working his way through right shoulder inflammation, which landed him on the 15-day injured list Sept. 14. Barring any setbacks Tuesday, the 26-year-old could be activated after a minimum-length stay, which would line him up for the weekend series against the Padres that begins Friday. Manger Torey Lovullo told reporters Monday that whether Nelson operates as a starter or reliever will depend on what pitch count the right-hander can comfortably manage.