Pitching coach Scott Emerson said Puk (biceps) began a rehab assignment at Triple-A Las Vegas on Tuesday and will need "a couple more outings" before returning from the injured list, Martin Gallegos of MLB.com reports.
The 26-year-old threw 20 pitches and recorded three strikeouts over a scoreless frame in his first rehab appearance Tuesday with the Aviators. Puk landed on the injured list after covering 3.1 innings during his season debut April 5, and he could return sometime next week if all goes well on the rehab stint.