Or was his four-hit shutout against the Rockies simply one gem among numerous subpar outings during his San Francisco tenure?
Zito gets his first chance to provide the answer to those questions Saturday at AT&T Park, when he and the Giants face the Pirates and right-hander Charlie Morton, who is expected to make his 2012 debut.
Zito has gotten off to a hot start before. He began the 2010 season 5-0 with a 1.49 ERA and was 7-2 on June 12. His season nosedived after that, however, as Zito won only two more games and was left off the eventual world champions' postseason roster.
Taking the mound for the Pirates is Morton, who posted a career-best 3.83 ERA a year ago. The right-hander would be making his first start of 2012 after beginning the season on the disabled list while rehabbing from offseason surgery on his left hip.
The Pirates will no doubt be thrilled to get their ace back, but they don't necessarily need another arm. Pittsburgh has a 2.66 ERA, including a 2.88 mark from its starters. The Pirates' offense, meanwhile, has been punchless. Pittsburgh managed only one hit and struck out 11 times against Giants starter Matt Cain on Friday and in its three previous losses was 0-for-14 with runners in scoring position.
Although Morton likely won't bring any offense, he should easily slide back into the rotation. He was impressive Monday in a rehab start for Triple-A Indianapolis, allowing one run on six hits and striking out eight in 7 2/3 innings and said he's good to go.
"I've been ready. I'm really eager to get back out there," Morton said. "This has been a strange spring for me; I've never before had to go at a slower pace than everyone else. But it's all come together, and last time out everything was working."
Pirates: Forgotten weapon
Joel Hanrahan proved to be one of the best closers in the Majors a year ago, saving 40 games in 44 opportunities. But with both of Pittsburgh's wins being walk-offs and the club mired in a four-game losing streak, Hanrahan has yet to pitch in a save situation this season. He gave up a two-run homer in the eighth inning Friday.
Pirates catcher Rod Barajas is a .297 (11-for-37) career hitter with three home runs against Zito.
Giants: Home cooking
The Giants improved to 10-3 in home openers at AT&T Park with Friday's win and have taken quite well to their park since it opened in 2000. San Francisco's .557 home winning percentage since 2000 was, entering Friday, the third-highest in the Majors in that span, trailing only the Cardinals (.605) and Braves (.587).
The Giants have started the season averaging 5.43 runs per game and have scored four or more runs in all seven games. The last time the Giants opened the season scoring at least that many runs in consecutive games was 2003, when they scored four or more in nine straight.
Right-hander Dan Otero has changed his number from 87 to 37.
Giants center fielder Angel Pagan is hitting .778 (7-for-9) against Morton in his career.
The Pirates have walked only twice in their last four games and have drawn a Major League-low seven free passes on the season.