Mayer will rest through the weekend before being re-evaluated early next week. He initially landed on the 10-day injured list in late June with a left forearm stress reaction while still with the Red Sox, before getting sent west at the trade deadline. The 23-year-old has played four rehab games with Triple-A Sacramento, going 6-for-17 with one home run and a 2:9 BB:K. Mayer had appeared in line to make his Giants debut early next week, but that plan is likely on hold.

Vitello had previously floated the possibility of Mayer being activated from the 10-day injured list this weekend, and while a return to action for the team's series in Boston hasn't been ruled out, the Giants seem to be leaning toward waiting until the start of a homestand Monday to reinstate the infielder. Mayer has been out since late June with a left forearm stress reaction but has played four rehab games with Triple-A Sacramento, going 6-for-17 with one home run and a 2:9 BB:K while making three starts at second base and one at third base. Once activated, Mayer should be in line for an everyday role in the San Francisco infield.