By JEFF BARTL
(AP) -- The San Francisco Giants' slump is largely due to the struggles of their starting pitchers, and Ryan Vogelsong may need to turn things around quickly before he loses his spot in the rotation.
He'll face a Washington Nationals team that has struggled offensively of late in the opener of a three-game series Monday night in San Francisco.
The Giants (24-20) lost five of six on their road trip with the starters posting a 9.82 ERA while allowing at least five runs in each contest. The club wasn't much better at the plate in a 5-0 loss to Colorado on Sunday.
Manager Bruce Bochy, though, isn't concerned about his currently ineffective rotation.
"It's a temporary thing. You don't have the success we've had and not be good, these pitchers," Bochy said. "It's a great starting rotation. They've done some remarkable things for us, but at the same time it's a new year and we've got to make some adjustments."
Vogelsong (1-4, 8.06 ERA) may not be getting more votes of confidence from Bochy if he can't bust out of his funk. He's winless in his last six starts and 0-3 with an 11.81 ERA over his last four.
The right-hander gave up a career worst-tying eight runs - though only three earned - in two innings of an 11-3 loss to Toronto on Wednesday.
Vogelsong has pitched fewer than five innings in each of his last three outings.
"Things have got to turn in my favor here eventually," Vogelsong said.
There had been speculation Bochy would bypass him in the rotation, but Vogelsong still is scheduled to go Monday.
"He's fighting, I'll say that," Bochy said. "I know he's taking it hard. He'll get on track."
Vogelsong's only start versus Washington didn't go very well, as he allowed eight runs and nine hits in 2 2-3 innings of a 14-2 defeat Aug. 13.
He'll face a Nationals team that's lost six of nine after falling 13-4 to San Diego on Sunday. Washington has scored two or fewer runs five times and is batting .211 during that stretch.
"The lineup is not swinging the bats very good," manager Davey Johnson said. "I like the way the pitching has been. Sometimes, it just takes time to jell."
Johnson will hand the ball to Zach Duke on Monday to give him some extra work as he makes his first start since July 10, 2011, with Pittsburgh.
Duke (0-0, 8.40) has struggled in his last two appearances. He gave up three runs in three innings of an 8-1 loss to Atlanta on April 30 before allowing four runs in two-thirds of inning as Washington fell 8-2 to the Chicago Cubs on May 11.
"I haven't able to give him the kind of work to keep him sharp," Johnson told the team's official website. "This will help him get back to where he needs to be. It kills two birds with one stone."
The left-hander, 1-0 with a 1.23 ERA in three career starts in San Francisco, will be taking the place of Ross Detwiler, who suffered a lower back injury Wednesday.
Duke likely will be facing the hot-hitting duo of Marco Scutaro and Buster Posey after Bochy gave both players the day off Sunday. Scutaro is batting .486 during a 17-game hitting streak while Posey has batted .340 with 12 RBIs in his last 15.
"He's been on a great run here," Bochy said of Scutaro. "Sometimes, you've got to give him a break."
Updated May 19, 2013