Pittsburgh @ San Francisco preview

Last Meeting ( Aug 9, 2011 ) Pittsburgh 0, San Francisco 6

THE STORY: After ending their 10-game skid in the series opener, the Pittsburgh Pirates resorted back to their losing ways Tuesday. But they still have a chance for their first series victory in six tries when they meet the San Francisco Giants in the finale of their three-game set Wednesday afternoon. San Francisco also has struggled of late, losing its last three series and dropping nine of its last 12 games.

TV: 3:45 p.m. ET, Root Sports (Pittsburgh), CSN Bay Area (San Francisco)

PITCHING MATCHUP: Pirates RH Jeff Karstens (8-6, 3.05 ERA) vs. Giants LH Jonathan Sanchez (4-6, 4.10 ERA).

Karstens is coming off his worst start of the season, a 15-5 loss to San Diego on Friday in which he allowed a season-high nine runs in just 3 1/3 innings. The 28-year old had surrendered a total of eight earned runs in his previous five outings. Karstens, who is 3-0 in his last six road starts, yielded five runs - two earned - over 6 2/3 innings in a loss to San Francisco on April 28.

Sanchez will be making his second start since a stint on the disabled list. He allowed five runs over 4 2/3 innings against Philadelphia on Friday in losing his third straight decision. Sanchez, who has won just once in his last nine outings, has not yielded an earned run against Pittsburgh in 14 1/3 innings.

ABOUT THE GIANTS (64-53): Each of San Francisco's last 18 home runs have been solo blasts. Chris Stewart and Aubrey Huff each went deep with the bases empty in Tuesday's victory, with Stewart's shot being his first in 140 career at-bats in the major leagues. Nate Schierholtz hit the Giants' last non-solo homer, a two-run blast against San Diego on July 6. Prior to its six-run outburst on Tuesday, San Francisco had the lowest run total (67) in the majors since the All-Star break. Carlos Beltran missed his second straight game with a right hand injury.

ABOUT THE PIRATES (55-60): Pittsburgh has served up 17 home runs in its last eight games. The Pirates registered only five hits Tuesday, but three were doubles. Ross Ohlendorf made his final rehab start for Triple-A Indianapolis on Tuesday, allowing four runs and eight hits in 6 1/3 innings. Ohlendorf, who has been on the disabled list since April 9 with a strained shoulder, is expected to be activated by the end of the week.

FINAL PITCH: The Giants have not lost four consecutive series since June 22-July 4, 2010. During that stretch, they posted a 3-10 record.