Other than every game in which he's given up multiple earned runs, Zito's been a godsend for this team.
Zito had another strong start, though it's hard to get too excited about a six-walk outing. But Zito's still worth a major league roster spot, and he has been since he's been a Giant. Releasing him -- while it would be a spiffy, head-on-a-pike/ornamental kind of move -- never made baseball sense. It's hard to remember that during the games he's handing out complimentary runs, so today feels like a good time to revisit that point.
If other teams commit errors at crucial times over the next fifty games, the Giants have a shot to make some noise in this playoff race.
Last point: I think it's ridiculous that AAA rules prohibit pitchers from throwing low-and-in sliders to left-handed hitters. It's an archaic, unnecessary rule, and it doesn't help when teams want to evaluate their own prospects. Like, oh, John Bowker. There's absolutely no way he's ever seen a slider at his back foot, and that's not fair to him or the team when he reaches the majors.
edit: Upon further review, it seems like I was a little too "meh" about Zito's performance. A lot of walks, sure, but he could have crumpled under the pressure at any point. And there had to have been a lot of pressure on this start. Bully for you, Zito. Bully.