Third base umpire Doug Eddings, right, signals a balk on San Diego Padres' Edinson Volquez as Arizona Diamondbacks' Adam Eaton points at the pitcher as well during the fifth inning of a baseball game Sept. 19, 2012 in Phoenix.(AP Photo/Ross D. Franklin)
PHOENIX (AP) — Edinson Volquez found one bright spot in the midst of the San Diego Padres' loss Wedneday.
For the first time in six years, the right-hander did not walk a batter.
"That is pretty good," said Volquez, who had walked at least one hitter in each of his past 108 starts, including six in his last outing Sept. 11 against St. Louis. "It felt good not walking anybody today."
Volquez (10-11) gave up four runs and eight hits over six innings. He struck out five and did not walk a hitter for the first time since Sept. 25, 2006, for Texas against the Los Angeles Angels.
Three of the runs came during the fifth inning, when the Diamondbacks pieced together four hits, a hit batter and a balk to overcome a 2-1 lead.
"It was a bad inning. Just one inning," Volquez said. "I was under control the whole game but that one inning I gave up a few runs and that was the whole game."
With the Diamondbacks trailing, 2-1 John McDonald reached on an infield single to start the fifth. He went to second on a sacrifice and scored on Adam Eaton's triple to left-center field — his first career RBI in 44 at-bats and his first career triple.
"Usually the left-center field gap is the hardest place to get a triple, or maybe down the left-field line," Eaton said. "If you can get a triple to the left-center field gap you've got the horses going a little bit."
Eaton scored when Volquez was called for a balk for starting his motion, shifting his left foot back before taking his right foot off the rubber as Eaton crept down the line.
Volquez said he thought the umpire had called time out.
"He (the umpire) did something with his mask and then I stepped off with the wrong foot," Volquez said. "That was bad because there was a guy on third base and he scored."
Justin Upton and Paul Goldschmidt each hit RBI doubles to make it 4-2.
"It came down to that three-run inning," Padres manager Bud Black said. "They strung together some hits and we didn't. They bunched them together that inning."
Max Venable and John Baker had consecutive RBI singles for the Padres, who have lost two straight to the Diamondbacks after winning eight of their previous nine against them.
"We didn't get as many baserunners tonight as we have over the last couple of months," Black said.
Dan Wheeler had an RBI triple and Montero added a run-scoring double for the Diamondbacks, who have won three straight. Arizona remained 4 1-2 games behind St. Louis for the second NL wild card.
The Diamondbacks are .500 since they were 64-64 on Aug. 26.
Arizona starter Trevor Cahill (12-11) went six innings, allowing two runs and five hits with four walks and four strikeouts. Two of his walks and four of his baserunners came in the Padres' two-run third.
Montero made it 2-1 in the bottom of the fourth when he doubled home Upton, who led off the inning with the first of his two doubles.
Arizona extended its lead to 6-2 in the eighth when Brad Boxberger hit Montero with a pitch, Wheeler tripled and second baseman Logan Forsythe's relay throw sailed into the Diamondbacks dugout to allow Wheeler to score.
NOTES: Diamondbacks reliever Brad Ziegler induced his 18th double-play grounder of the season, the most by a relief pitcher in the majors since Jeremy Affeldt also recorded 18 GIDPs in 2009 for San Francisco. .. Cahill's four walks were his most since a four-walk outing June 27 at Atlanta. ... Goldschmidt became the fifth Arizona player — and first since 2008 — with 40 doubles in a season. ... Carlos Quentin, playing for the first time since Sept. 10 because of pain in his surgically repaired right knee, left the game in the fourth after going 1 for 2. Black said Quentin "was a little uncomfortable." . Cahill joined C.C. Sabathia of the Yankees as the only pitchers since 1990 to record 10 wins and 30 starts in each of his first four seasons. . Padres RHP Andrew Cashner, who gave up six runs in 3 2-3 innings on Friday, told reporters Wednesday he's done for the season with lingering soreness in his right lat muscle. Cashner finishes the season 3-4 with a 4.37 ERA in 32 games and five starts. ... San Diego CF Cameron Maybin missed his second straight game with a sore left Achilles tendon. ... Before the game, the Diamondbacks recalled OF A.J. Pollock from Triple-A Reno and also selected the contract of IF Mike Jacobs from Reno. Arizona designated OF Cole Gillespie for assignment to make room on the 40-man roster for the 31-year-old Jacobs, who served a 50-game suspension in 2011 and into the start of 2012 for using HGH. "He did his 50 games," Gibson said. "He played the season in Triple-A and was a good leader down there." ... LHP Tyler Skaggs (1-2) will look to snap a two-game losing streak when he takes the mound for Arizona against Padres LHP Clayton Richard (13-12) in a getaway day afternoon game Thursday. Richard is 5-0 with a 3.80 ERA in eight career starts against Arizona.