Right-hander Edinson Volquez can get back to .500 for the first time since late July when the San Diego Padres visit the Arizona Diamondbacks in the finale of a three-game series at Chase Field.
Volquez, in his first season with the Padres after four with Cincinnati, was 2-2 in mid-May before dropping four straight decisions. He climbed back to 7-7 after beating the Reds on July 30, but fell back to 7-9 before a 3-1 decision over Pittsburgh in his last start Aug. 20.
In that game, the Dominican allowed a run on five hits - with 10 strikeouts - in 6 2/3 innings.
He picked up 17 of his 41 career major-league wins in his first season with Cincinnati in 2008, after he was acquired from Texas for Josh Hamilton.
In five starts against Arizona, he's 0-1 with a 4.15 earned run average.
The Diamondbacks go with skidding lefty Joe Saunders, who meets the Padres for the 10th time in his 183rd career start.
A former first-round pick of the Angels, Saunders was 4-4 after a 4-3 interleague defeat of Oakland on June 10, but has since won just twice in nine starts to fall to 6-10 overall.
He was raked for 12 hits and nine runs in just 3 2/3 innings of his last outing on Aug. 20, when he dropped a 12-3 decision to Miami,
Saunders is 5-3 in his first nine meetings with San Diego while carrying a 2.67 ERA through 64 innings.
On Saturday, Clayton Richard pitched eight innings and San Diego matched a season-high with its sixth straight win, 9-3. Chase Headley, Carlos Quentin and Yonder Alonso homered off Ian Kennedy, as the Padres won their sixth in a row at Chase Field.
Richard (11-12) gave up seven hits and three runs, including a pair of homers. The lefty has won four of his last five starts, and has pitched at least eight innings in three of those games. He's 5-0 in seven career games against the Diamondbacks.
Justin Upton, who celebrated his 25th birthday, hit a two-run inside-the-park homer for Arizona. Aaron Hill also went deep for the Diamondbacks, who will try to avoid the three-game sweep Sunday.
Kennedy (11-11) allowed four hits and six runs over 5 1/3 innings to lose for the first time in seven career decisions against the Padres.
San Diego won five of the initial nine games between the teams in 2012, including a three-game sweep in Phoenix from July 2-4. Arizona won the series last year, 11-7.