When the San Francisco Giants acquired Jake Peavy prior to the trade deadline, they were hoping a change of scenery would snap the veteran right-hander out of the longest funk of his career. Peavy, though, is still trying to push his way into the win column as he takes a 12-game losing streak - and 18-game winless string - into Wednesday's two-game series finale against the visiting Chicago White Sox. San Francisco is fading fast from the National League West race as it dropped six games behind the Los Angeles Dodgers with Tuesday's 3-2 loss, but remain in the thick of the wild card race, one-half game behind St. Louis for the second spot.Another trend the Giants must reverse is their play at home as they have lost 22 of their last 29 contests at AT&T Park after winning 22 of their first 31. Chicago, which has won six straight against San Francisco, improved to 2-3 in a stretch of playing 15 straight games against winning teams. The White Sox's Jose Quintana - coming off his first loss since June 13 - starts in place of Scott Carroll, whose turn was skipped because of a blister.TV: 3:45 p.m. ET, WGN (Chicago), CSN Bay Area (San Francisco)PITCHING MATCHUP: White Sox LH Jose Quintana (6-8, 3.04 ERA) vs. Giants RH Jake Peavy (1-12, 4.73)Quintana allowed four runs (two earned) and seven hits in 5 2/3 innings of a 4-1 loss to Seattle on Friday after going 3-0 in his previous nine starts. The 25-year-old Colombian has a 1.82 ERA over his last 10 turns while Chicago scored four or more runs only three times during that span. Quintana, who has never faced San Francisco, is 3-3 with a 2.08 ERA in 10 interleague outings - 1-2, 2.37 in three starts this season against Colorado (win), Arizona and the Los Angeles Dodgers.Peavy yielded three runs and nine hits in 5 2/3 innings of a 3-1 loss at Milwaukee on Thursday to fall to 0-3 with a 4.82 ERA in three starts since he was acquired from Boston on July 26. ''He battled well (Thursday),'' Giants manager Bruce Bochy told reporters about the 33-year-old Alabama native. ''He gave us a gutty effort. He kept us there in the game. Gave us a chance. That's what you want from your starter.'' Peavy, who was 28-25 in three-plus seasons with Chicago from 2009-12 and is 133-110 in his career, received a no-decision in a 2-1 loss to the White Sox on April 15 when he struck out eight in six innings.WALK-OFFS1. Giants RHP Matt Cain on Tuesday underwent right elbow surgery and following a three-month recovery period is expected to be ready for spring training.2. Chicago RHP Jake Petricka on Tuesday blew his third save in 11 chances as the White Sox recorded their 18th blown save - tied for third with Pittsburgh, and trailing only Houston (22) and Colorado (20).3. San Francisco has scored nine runs during its losing streak while Chicago has scored 12 in its last seven contests.PREDICTION: White Sox 3, Giants 2