By JEFF MEZYDLO
(AP) -- Tim Lincecum is mired in the worst start of his six-year career. Facing the Arizona Diamondbacks might not make things any better.
Ian Kennedy is in the midst of his longest personal losing stretch, but has fared well against the San Francisco Giants of late.
The struggling aces match up Wednesday night when the Giants look to complete a three-game sweep with their fifth straight win over the visiting Diamondbacks.
Lincecum (2-5, 6.41 ERA) last won April 28 when he allowed an unearned run in eight innings of a 2-1 victory over San Diego. Since then, the two-time Cy Young Award winner is 0-3 with a 7.09 ERA in five May starts. He has not gone an entire month without earning a win since he was 0-5 with a 7.82 ERA in August 2010.
"He's taking it hard, believe me," manager Bruce Bochy told the Giants' official website.
The right-hander gave up one run through five innings before yielding five in the sixth of a 7-6 loss at Miami on Friday. It's the third time in four starts Lincecum allowed at least four runs in a single frame.
"If I could just eliminate that one bad inning, wherever it falls, that's the big thing," Lincecum said.
His season began on a rough note when he allowed five runs and two homers in 5 1-3 innings of a 5-4 loss at Arizona on April 6. Lincecum has posted a 6.85 ERA while losing four straight outings to the Diamondbacks.
Kennedy (3-5, 4.65) gave up three runs in 6 2-3 innings of that opening day victory over Lincecum to improve to 5-2 with a 2.09 ERA in 11 starts versus San Francisco.
Though the right-hander has a 2.60 ERA while winning four straight starts against the Giants, he's not won since April 22 and owns a 6.00 ERA while losing five consecutive outings. The Diamondbacks (22-28) have scored two runs with Kennedy on the mound in those contests.
"I am trying to figure out what it is every single time," said Kennedy, who went 21-4 with a 2.88 ERA in 2011. "Whether it is mechanical or other things I have to keep the same approach and throw every pitch with conviction."
He gave up four runs and seven hits - two homers - in 5 2-3 innings of a 7-1 loss to Milwaukee on Friday. Kennedy has surrendered seven homers in his last four starts - the same number he'd allowed in his previous 19 regular-season outings.
"He is not being able to locate the ball," manager Kirk Gibson said. "I don't think he is locating the ball down like he used to. He is not able to throw secondary pitches for strikes like he did. He is close. It is just too much elevation with his pitches."
Melky Cabrera, 4 for 7 with a homer off Kennedy, had three hits in San Francisco's 3-1 win over the Diamondbacks on Tuesday. The Giants (27-23) have won three in a row and 12 of 18.
Cabrera's 50 hits are the most in May by a San Francisco player - breaking Willie Mays' record - and are one shy of the record for any month set by Randy Winn in September 2005. He's hitting .486 (17 for 35) versus Arizona in 2012.
"I've never seen anything like it," teammate Ryan Theriot said of Cabrera, who leads the majors with 77 hits. "He hits the ball hard, he's getting a hit. He doesn't hit the ball hard, he's getting a hit. It's awesome. It couldn't happen to a better guy."
Justin Upton had one of the six hits Tuesday for Arizona, which has totaled three runs and gone 4 for 20 with runners in scoring position in the series.
Upton is batting .349 in his last 12 games, but is 4 for 19 with seven strikeouts versus Lincecum since 2010.
Updated May 30, 2012