Mayer (forearm) went 1-for-2 with a walk and a solo home run Thursday in his first rehab game with Triple-A Sacramento.
Mayer showed no rust in his first game in nearly two months, hitting a laser over the center-field wall in his second plate appearance. He played five innings at second base before being lifted. Per Alex Pavlovic of NBC Sports Bay Area, the Giants don't think Mayer will need many rehab games before joining the big-league roster. Mayer has been sidelined since late June with a stress reaction in his left forearm.