Sanchez, 28, said after pitching 4 2/3 innings Friday night against Cleveland that he felt "healthy" and "fine." But he admitted Saturday that his arm felt sore during his previous three starts. Bochy pointed out that Sanchez's velocity dropped noticeably in the early innings during his start Friday.
Sanchez had hoped to endure his next three starts, which would have brought him to the All-Star break and, he thought, might have given him sufficient time to rest his arm.
Sanchez leads the National League with 59 walks, including 25 in his last 25 2/3 innings, and six on Friday. He also hit Cleveland's Shin-Soo Choo with a pitch that broke the right fielder's left thumb. Sanchez finally acknowledged that he was devoting too much energy to "fighting through" his injury.
"We did the best thing for the team and for me," said Sanchez, who's 4-5 with a 3.81 ERA in 16 starts. "I wasn't pitching well, we need to win some games and I need to get better."
Sanchez, who underwent an MRI exam and was examined by doctors Saturday, said that he will take a week off from throwing before his next course of action is determined.
Bochy explained that Zito was activated Saturday instead of Tuesday, when he's expected to start the second game of a day-night doubleheader at Chicago, because the Giants planned to rest right-hander Sergio Romo on Saturday and needed a full complement of pitchers in case extra innings unfolded.
"You never know what could happen in a game," Bochy said. "We just wanted Zito available."
Bochy noted that some consideration is being given to starting Tim Lincecum instead of Zito on Tuesday. In that event, Zito would pitch Wednesday.
Sidelining Sanchez presented a minor issue for the Giants. Assuming they move up Matt Cain and Madison Bumgarner to pitch Thursday and Friday, respectively, they'll need a new starter next Saturday in Detroit to prevent any of the existing starters from working on short rest. Most likely, the Giants will dip into their bullpen to fill that spot.