Mayer (forearm) could be cleared to begin a rehab assignment next week, Alex Pavlovic of NBC Sports Bay Area reports.
Mayer landed on the injured list in late June due to a stress reaction in his left forearm. He has since been traded from Boston to San Francisco and now seems to be on the verge of making his organizational debut following multiple weeks of hitting and fielding drills. Because he's been on the shelf for more than a month, he'll likely require a handful of reps in the minors before being cleared to play his first game as a Giant.