Wacha (shoulder) threw 25 pitches in a bullpen session Tuesday, per MLB.com.
The bullpen was Wacha's first since he landed on the injured list July 4. The veteran hurler threw only fastballs and changeups in the session, and he's expected to mix in the rest of his pitches in another bullpen Friday. If that goes well, Wacha could return to the Padres' rotation in early August.