Giants starting rotation losing its grip

Jorge L. Ortiz | USA TODAY Sports

What was once the bedrock of two World Series championships has turned into a liability that threatens the San Francisco Giants' chances to repeat. Their rotation ranks third-to-last in the National League with a 4.89 ERA. Before long reliever Chad Gaudin came to the rescue with six strong innings in a spot start Sunday, the Giants starters had combined for three quality starts and a 6.54 ERA in the previous 18 games. USA TODAY Sports' Jorge L. Ortiz looks at the once-vaunted starting five and the issues they face:

Pitcher: Matt Cain

In the past: Cain threw a perfect game in 2012, his third season as an All-Star and the best of his career. He assumed the mantle of staff ace and earned a six-year, $127.5 million contract.

This year: Cain's 13 homers allowed lead the league, and he has been victimized by big innings. On Saturday, the St.Louis Cardinals scored at least seven runs in an inning against him for the second time this year, inflating his ERA to 5.45.

The upshot: Cain and pitching coach Dave Righetti agree the problem has been wildness in the strike zone. "Instead of walking guys, I was throwing balls in the sweet spot for guys to hit," said Cain, who was a lot sharper in May (4-0, 3.48 ERA) before the Cardinals got to him Saturday.

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Pitcher: Tim Lincecum

In the past: A two-time Cy Young winner, Lincecum had what was regarded as an off year in 2012, when he had the highest ERA (5.18) and most runs allowed in the NL. Those numbers are now starting to look like the new normal.

This year: Lincecum's 5.12 ERA is nearly identical to last season's, puzzling because his strikeout ratio of 9.4 per nine innings remains close to his career norm of 9.7. His fastball command continues to be erratic, leading to walks, high pitch totals and unfavorable counts.

The upshot: Lincecum's success as a reliever in the 2012 postseason and his struggles during the season prompted talk about what might be his best role in the future. The Giants don't have anybody to take his rotation spot, so they can't afford to make that move now, but manager Bruce Bochy acknowledges Lincecum has been "a bit of an enigma."

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Pitcher: Madison Bumgarner

In the past: A paragon of consistency in his first three seasons, Bumgarner won a career-best 16games last year and ranked 12th in the NL with a 3.37 ERA, pitching most of the season at age 22.

This year: Bumgarner was the Giants' only reliable starter in April, then fell into a funk in May (5.17 ERA) and has not bounced back. He's 4-4 with a 3.46 ERA overall.

The upshot: With his deceptive delivery, sharp stuff and workhorse build, the lefty probably worries the Giants brass less than any other starter. Bumgarner is allowing fewer than seven hits per nine innings, and, while his command hasn't been as good as usual, a turnaround might soon be in the offing.

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Pitcher: Barry Zito

In the past: Zito did not enjoy a winning season in San Francisco until 2012, when he finally paid off on his mega contract by going 15-8 and saving the season with a brilliant performance in Game 5 of the NLCS.

This year: A 4-3 record and 3.88 ERA would seem like acceptable numbers for a back-of-the-rotation starter, but they don't tell the whole story. Zito has thrived at AT&T Park (4-0, 1.40 ERA) while getting shelled elsewhere (0-3, 10.19 ERA).

The upshot: It's hard to trust him on the road, but he's still capable of escaping jams despite a low-octane fastball.

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Pitcher: Ryan Vogelsong

In the past: Vogelsong gave the Giants two unexpectedly fine seasons after four years out of the majors, going a combined 27-16 in 2011 and 2012 and excelling in last year's postseason.

This year: Vogelsong lugged the majors' worst ERA at 8.06 into his May 20 start, then had to leave with an injury after his best outing of the season.

The upshot: A broken right pinkie is expected to sideline Vogelsong until after the All-Star break, and it's not clear how effective he will be when he returns. The Giants have tried to fill his void with rookie lefty Michael Kickham, who struggled in his lone start, and on Sunday with Gaudin. A permanent solution remains elusive.