Pittsburgh @ San Diego preview

Last Meeting ( Aug 21, 2012 ) Pittsburgh 5, San Diego 7

The San Diego Padres can do no wrong against the Pittsburgh Pirates and they'll go for a three-game sweep Wednesday at Petco Park. The Padres, who have won 17 of the last 20 meetings, defeated the Pirates on Tuesday 7-5 in 10 innings on Chase Headley's two-run homer. Headley, who leads the majors with nine homers and 26 RBIs in August, isn't the only red-hot player in the Padres' lineup. Cameron Maybin and Will Venable matched career highs with four hits apiece Tuesday and are 9-for-13 and 9-for-14, respectively, in their last three games. Andrew Werner, a 25-year-old non-drafted left-hander out of Division II University of Indianapolis, will make his first major league start for San Diego, which has won four straight.

The Pirates, who haven't made the playoffs or had a winning season since 1992, are 19-19 since the All-Star break. They have lost three of their last four games and National League MVP candidate Andrew McCutchen is 4-for-23 with 10 strikeouts during that span. Pittsburgh, which has seen its lead for the NL's second wild card spot shrink to one-half game over St. Louis and Los Angeles, hopes James McDonald can reverse its fortunes. He is coming off his best start in seven outings since the All-Star break.

TV: 6:35 p.m. ET, Root Sports (Pittsburgh), FS San Diego

PITCHING MATCHUP: Pirates RH James McDonald (11-5, 3.61 ERA) vs. Padres LH Andrew Werner (NR)

McDonald resembled the pitcher who was 9-3 with a 2.37 ERA at the break when he allowed two hits and struck out seven in six shutout innings in Pittsburgh's important 2-1 victory at St. Louis on Friday. He was crushed by San Diego, though, two starts back when he yielded seven runs in 4 1/3 innings in Pittsburgh's 9-8 loss on Aug. 10. The Padres' roster is hitting .257 against McDonald, with Venable and Maybin a combined 0-for-11 and Headley 2-for-6, including a three-run homer in the last encounter.

Werner throws in the high 80s and features a curve and changeup. He was 1-2 with a 5.79 ERA in four starts with Triple-A Tucson and yielded seven runs and seven hits in 5 1/3 innings in his last outing. Werner was 4-8, 3.23 in 18 starts with Double-A San Antonio prior to his first promotion.

WALK-OFFS

1. Pittsburgh's Garrett Jones homered twice Tuesday, including a two-run shot against Dale Thayer to tie the game 5-5 in the ninth inning. It was San Diego's first ninth-inning blown save opportunity in 29 tries this season.

2. San Diego SS Everth Cabrera stole his 22nd base Tuesday and hasn't been caught this season. The single-season record is 23, set by Philadelphia's Chase Utley in 2009.

3. Padres RHP Luke Gregerson worked a scoreless eighth Tuesday for the second straight night to extend his scoreless innings streak to 19 2/3, a span of 20 games since July 4.