Zito said that he approached Bochy after allowing four runs in 3 1/3 innings last Tuesday at Philadelphia and suggested that a change might be necessary.
"I came into his office after I pitched and I said I'm hurting the bullpen by not going six, seven innings," Zito said. He and Bochy subsequently discussed the option of a move to the bullpen, though the switch wasn't announced immediately.
"I told him I'm not getting down on myself or losing confidence or desire or inspiration," Zito added.
Zito's spot in the rotation seemingly has been in jeopardy for much of the season. He's 4-8 with a 5.09 ERA in 21 starts, including 0-7, 9.97 in nine road assignments. The Giants are 2-8 in the last 10 games started by Zito, who's 0-5 with a 6.66 ERA in that span. He has one victory in his last 17 outings.
The contrast is stark between this year and last season, when the Giants were winners in Zito's final 14 starts, including the postseason.
Bochy said that during the foreseeable future, Zito, who's in the final season of a seven-year, $126 million contract, will perform in long relief.
Bochy mentioned that another factor in Zito's demotion is the imminent return of right-hander Ryan Vogelsong, who could be activated from the disabled list after making his fourth Minor League injury rehabilitation start this Sunday. Vogelsong can easily occupy Zito's spot in the rotation, since he's pitching on the same schedule -- unless Moscoso pitches well enough to deserve another start.
Mostly, Bochy decided that it simply was time for a change, given Zito's struggles.
"How long this will be, I can't tell you," Bochy said. "But it was time to mix it up, change it up."
Bochy acknowledged that the Giants have discussed trying a six-man pitching rotation once Vogelsong returns, which could be as soon as next Friday. But that would require expanding the pitching staff from 12 to 13 men, Bochy said.