Clarke (hamstring) has started to play catch and has also begun a swinging progression, Martin Gallegos of MLB.com reports.
Clarke originally landed on the injured list in April due to a bone bruise in his foot, but he strained his left hamstring while playing in a rehab game in late May. He's still expected to remain sidelined through the All-Star break, though his return to activity is an encouraging sign of progress in his recovery. That said, Henry Bolte has filled in admirably as Clarke's replacement in center field, so the latter may not have much of an impact on the big club once he's activated.