Dempster, who holds a $14 million player option for next season, is 0-5 in eight starts since his last victory on Aug. 11. The 34-year-old did pitch well enough to win his last time out in St. Louis on Friday, holding the Cardinals to a run over six innings despite four hits and six walks.
The right-hander is 10-13 with a 4.53 earned run average this year and will face the Padres for the first time in 2011. Dempster has made 21 career appearances against them, including 12 starts, and is 8-4 with a pair of saves and 3.73 ERA in that time.
Tonight's finale could also be the last in a Cubs uniform for third baseman Aramis Ramirez, who has a $16 million club option for next season. Ramirez is hitting .306 with 26 homers and 93 RBI in 148 games this year and returned from a four-game absence due to a strained right quad in last night's 6-2 win.
"I'm going to try and improve. That's all I can do. I've got another year under my belt and a couple more lessons learned," Garza said about his season after Chicago snapped a three-game slide.
While the future of Ramirez and Dempster is cloudy, it remains bright for Cubs shortstop Starlin Castro. He had two hits in last night's win to give him 206 on the season and extend his run of reaching base safely to 39 straight games, the longest ever by a Cubs shortstop. The 21-year-old is also the youngest player in team history to reach 200 hits in a season.
Chad Qualls surrendered Soriano's homer to take the loss. Anthony Bass made his third start of his career and allowed one run on five hits and two walks through five full frames.
"I like the way he mixed his pitches today," Padres manager Bud Black said about Bass. "We're seeing a guy who looks as though he feels he belongs."
Kyle Blanks knocked in both of the Padres' runs as they were defeated for the third time in five games.
Wade LeBlanc takes the hill for San Diego tonight and had a two-start win streak halted on Friday versus the Dodgers despite seven innings of two-run ball in which he struck out a career-high 10 batters. The 27-year-old southpaw is 4-6 with a 4.83 ERA in 13 starts this year and has shown increased arm strength that could help him stay in the rotation for next year.
"I don't think his velocity wavered through seven innings," Black said.
LeBlanc will face the Cubs for the first time in his career.
The Cubs took two of three over the Padres at home back in April and won three of four at San Diego a season ago.