Natera (back) will begin a rehab assignment Friday with Single-A Rancho Cucamonga, Rhett Bollinger of MLB.com reports.
Natera landed on the 15-day injured list less than a week ago after experiencing lower-back spasms, but he resumed mound work Tuesday and is nearing a return to game action. The lefty reliever is eligible for activation Sept. 1 and is tracking toward a return on that date.