Zych (right shoulder biceps tendon transfer) started a light throwing program on Thursday, Ryan Divish of the Seattle Times reports.
Zych underwent right shoulder biceps tendon transfer surgery in October, and has recently started rehabbing in Arizona. He will be reevaluated before the season, and he could be close to being ready by the end of spring training. With Edwin Diaz locked into the closer role, Zych will be primarily used as a middle-relief option when he returns.