Webb (shoulder) threw a successful bullpen session Monday, Alex Pavlovic of NBC Sports Bay Area reports.
The right-hander resumed throwing last week and is now back to working off a mound. He's been battling a right shoulder strain since mid-May, though he did return from the injured list to make one start in late May before landing back on the shelf. Webb figures to require a rehab assignment before rejoining the starting rotation this time around.