Opponent: Chicago Cubs (45-63).

Site: Wrigley Field, Chicago.

TV, radio: All games on FSN Pittsburgh, KDKA-AM (1020) and Pirates Radio Network.

Starting matchups: LHP Tom Gorzelanny (1-2, 5.84) vs. RHP Carlos Zambrano (12-3, 3.26), LHP Zach Duke (7-9, 5.26) vs. RHP Mark Prior (0-5, 7.20), RHP Ian Snell (9-7, 4.66) vs. RHP Rich Hill (1-4, 7.92).

Season series: Chicago, 3-2.

Three things to know about the Cubs: 1. They are playing their best baseball of an otherwise miserable season, having won eight of 11, averaging 5.45 runs in that span. 2. After a dreadful start, 3B Aramis Ramirez has come alive in the past month, including nine home runs in his past 15 games. No player in Major League Baseball at his position has more home runs than his 25. 3. Zambrano was National League pitcher of the month for July by winning all six starts with a 4.15 ERA and 40 strikeouts. His 152 strikeouts are most in the league, and his opponents' batting average of .199 is the league's lowest.

The Pirates' key to success: Keep those starters rolling. In the past eight games, the rotation is 5-1 with a 2.36 ERA.

The intangible: A fight for fifth? Hey, the Pirates are only 4 1/2 games in back of the Cubs.

On deck: The six-game trip continues with three in Houston.