Sanchez returned from visiting Dr. Michael Collins, a Pittsburgh-based expert on sports-related concussions, who urged the 24-year-old switch-hitter to refrain from baseball-related activities for at least three more weeks and limit his workouts to light exercising.
"There's nothing he can do about it," Bochy said of Sanchez. "He just needs more rest."
Sanchez admitted Wednesday that he felt nauseous and dizzy during recent attempts to exercise. He added that he's having trouble sleeping and feels low on energy.
Sanchez said that Dr. Collins suggested a regimen of light exercises to perform, such as jogging and agility drills, and wants to re-examine him after three weeks.
"I have to be positive that I'll be fine," said Sanchez, whose progress was halted when he sustained his second concussion of the season earlier this month during a Minor League injury rehabilitation assignment with Triple-A Fresno.
In 66 games with the Giants this year, Sanchez has hit .196 with three home runs and 28 RBIs.
Chris Haft is a reporter for MLB.com. Read his blog, Haft-Baked Ideas, and follow him on Twitter at @sfgiantsbeat. This story was not subject to the approval of Major League Baseball or its clubs.