San Francisco @ San Diego preview

Last Meeting ( Aug 18, 2012 ) San Francisco 8, San Diego 7

The San Francisco Giants and their fans are becoming quite comfortable at Petco Park. With many of their vocal fans behind them, the Giants have won 14 of their last 19 games in San Diego and 19 of 25 overall against the Padres. San Francisco, which looks for a three-game series sweep Sunday, sits one-half game ahead of Los Angeles in the National League West. San Diego has been outscored 36-9 during its current five-game losing streak, although the Padres mounted a valiant comeback in Saturday’s 8-7 loss. Third baseman Chase Headley leads the majors this month with eight home runs and 24 RBIs.

A month ago, the Giants might have rested third baseman Pablo Sandoval and catcher Buster Posey on a day game following a night game, but not anymore. Both are expected to be in the lineup Sunday as San Francisco continues its playoff push. San Diego optioned Ross Ohlendorf to Triple-A Tucson on Saturday after another dismal outing, creating an opening in their rotation. Top prospects Casey Kelly and Robbie Erlin are considered possibilities, as well as veteran Kip Wells. The Padres’ bullpen could use a rest Sunday after working 14 innings over the last three games.

TV: 4:05 p.m. ET, CS Bay Area (San Francisco), FS San Diego

PITCHING MATCHUP: Giants RH Ryan Vogelsong (10-6, 2.72 ERA) vs. Padres LH Clayton Richard (9-12, 3.91)

Vogelsong is coming off his worst start of the season after giving up eight runs over 2 2/3 innings against the Nationals on Monday. Vogelsong allowed as many runs Monday as he had in his previous five starts combined and saw his ERA rise from 2.27 to 2.72. He pitched well against San Diego earlier this season, giving up one run over seven innings July 23.

Like Vogelsong, Richard is looking to rebound from a dismal start. After going 2-0 with a 1.27 ERA over his previous three starts, he allowed five runs over 6 1/3 innings against the Braves on Tuesday. Richard has pitched well since the All-Star break, however, going 3-3 with a 3.91 ERA in seven starts. In three starts against San Francisco this season, Richard is 0-3 with a 7.64 ERA.

WALK-OFFS

1. San Francisco has won 11 of its last 15 road games since the All-Star break, outscoring its opponents 111-52.

2. Padres reliever Luke Gregerson has not allowed a run in his last 18 outings covering 17 2/3 innings, limiting opponents to a .161 average (10-for-62).

3. The Giants have responded well since OF Melky Cabrera was suspended 50 games for using a banned substance, scoring 22 runs in three games.