He'll try to correct some underwhelming numbers at AT&T Park when the Giants welcome the Pittsburgh Pirates for the start of a three-game series Monday night.The Giants (57-48) have dropped four straight after Sunday's 4-3 loss to the Los Angeles Dodgers completed a three-game sweep and pushed them 1 1/2 games back in the NL West. Their latest round of offensive struggles features five runs scored and a .180 batting average during the losing streak. They've dropped 19 of 25 at home, marking the worst home winning percentage (.240) in the NL since June 9."It's going to be important to put it behind us," manager Bruce Bochy said. "We have to regroup."Bumgarner (12-7, 3.19 ERA) has won three straight starts with one run allowed over his last two, including eight scoreless innings of five-hit ball in Wednesday's 3-1 victory in Philadelphia."He gave us everything we needed and more," Bochy said.He's been unable to find a groove at AT&T Park this season, going 4-5 with a 5.22 ERA in 10 home starts with at least four earned runs surrendered in seven of them. From 2009-13, the 24-year-old went 23-16 with a 2.89 ERA in front of a home crowd.Pittsburgh (55-49) might be the right team to go about correcting that against. Bumgarner is 1-2 in three career starts against the Pirates but has a 1.71 ERA and .211 opponent batting average in those matchups with 22 strikeouts in 21 innings.The Pirates enter their second series on a 10-game trip against the NL West having lost eight of 11 on the road. They salvaged the finale of a three-game series in Colorado with Sunday's 7-5 victory while generating some confidence at the plate with 16 hits. Four of those came from leadoff hitter Josh Harrison."It was just fun to watch us play today with the energy and the effort that we played with after dropping the first two (which) weren't really close games," manager Clint Hurdle told MLB's official website.The Pirates took two of three from the Giants in Pittsburgh from May 5-7, collecting 33 hits in that series with Andrew McCutchen going 7 for 15.Vance Worley will get the opportunity to pitch Pittsburgh to its seventh win in 10 games since the All-Star break.Worley (3-1, 3.10) surrendered four runs -- one earned -- and seven hits in six innings of Tuesday's 12-7 win over the Los Angeles Dodgers. Despite some fielding issues behind him, Hurdle allowed the right-hander to work out of a sixth-inning jam and develop some trust in the clubhouse in his sixth start."You want your staff to believe in you out there," Worley said. "To be yanked out of there, you'd start to question yourself. It's all about how you bounce back after things like that happen."He made three starts against the Giants with Philadelphia from 2011-12, going 2-1 with a 4.09 ERA.San Francisco newcomer Dan Uggla is 5 for 11 with two homers off Worley. The second baseman is still looking for his first hit with the Giants and is 1 for 28 with 12 strikeouts over his last 19 games.Some of his new teammates can relate. Hunter Pence is 1 for his last 16 while Pablo Sandoval and Buster Posey are 2 for 14.