San Francisco @ San Diego preview

Last Meeting ( Jul 21, 2015 ) San Francisco 9, San Diego 3

The San Francisco Giants have identical 25-22 records at home and on the road but are a much different team offensively when playing in the other team's park as they visit the San Diego Padres on Wednesday afternoon in the rubber match of their three-game series. San Francisco leads the National League with 228 runs away from home - 52 more than they've scored at AT&T Park - after recording a 9-3 victory Tuesday without its best hitter in the lineup.

Giants manager Bruce Bochy decided to rest Buster Posey on the night before a day game and got the best of both worlds when his replacement - Hector Sanchez - belted a grand slam to help San Francisco snap a four-game slide in San Diego. The Giants, who trail only Toronto (244) in runs scored on the road, lead the major leagues with a .276 batting average away from home, and Posey is a big reason why. The All-Star catcher, who is hitting .323 on the road, owns a 10-game hitting streak away from home and is hitting .371 with three home runs and 10 RBIs during that span, and leads the majors with 38 RBIs on the road. The Giants are 2 1/2 games behind the first-place Los Angeles Dodgers in the NL West and one behind the Chicago Cubs for the final wild-card spot, while the Padres are 8 1/2 out and expected to be sellers prior to the July 31 trade deadline.

TV: 3:40 p.m. ET, CSN Bay Area (San Francisco), FSN San Diego

PITCHING MATCHUP: Giants RH Matt Cain (1-1, 5.06 ERA) vs. Padres RH James Shields (8-3, 3.92)

Cain received a no-decision after allowing four runs and eight hits in five innings of a 6-5 victory in Arizona on Friday in his third start of the season as he battles back from elbow surgery and a right flexor tendon strain. "I don't know exactly where I am right now," the 30-year-old Alabama native told reporters. "I've been around, but I've never missed the first half of the season. I don't want to give myself that leeway, but it kind of is the first month for me." Matt Kemp is hitting .237 with four homers among his 14 hits and 15 strikeouts in 59 at-bats versus Cain, who is 7-14 with a 3.18 ERA in 34 starts against the Padres.

Shields yielded one run, seven hits and four walks while striking out six in five innings of a 4-2 victory over Colorado on Friday to snap a seven-start winless streak. The 33-year-old Californian, who was 0-3 with a 4.97 ERA during his drought, walked four in three of his last four outings. Posey and Hunter Pence are a combined 1-for-21 while Brandon Belt has two triples in two at-bats against Shields, who fell to 2-1 with a 3.60 in three starts versus San Francisco after permitting seven runs and nine hits in four innings of a 13-8 loss at AT&T Park on June 25.

WALK-OFFS

1. Posey has hit safely in his last seven games (14-for-29) and is batting .417 in his last 19 contests.

2. Padres LF Justin Upton, an All-Star who is the subject of trade rumors, missed the last two games because of a left oblique injury and remains day-to-day.

3. Kemp was 14-for-31 with four home runs, four doubles and 10 RBIs during a season-high eight-game hitting streak which ended Tuesday, when he went 0-for-2 and was hit by a pitch.

PREDICTION: Padres 3, Giants 2