The San Diego Padres have won back-to-back games on several occasions this season, but have yet to complete the trifecta.

Thursday could be the day that happens for a Padres squad aiming for its first sweep of the 2012 campaign in the finale of a three-game series against the Seattle Mariners at Safeco Field.

The Padres put themselves on the brink of a sweep with Wednesday's 1-0 win in the Emerald City behind Jason Marquis's 6 1/3 shutout innings and Yonder Alonso's home run leading off the top of the seventh.

"Jason did a nice job keeping the ball below the strike zone, kept the ball at the knees when he needed to throw a strike, threw inside well with the fastball," Padres manager Bud Black said. "If you were to script out a Jason Marquis game, that's what it would look like."

Joe Thatcher, Luke Gregerson and Huston Street held the Mariners off the scoreboard the rest of the way, with Street notching his seventh save.

The Padres, who took a 5-4 decision in the opener of this set on Tuesday, have won two straight away from home for the first time since a three-game sweep at Colorado from September 19-21, 2011. The Padres posted their first series win since taking two of three from the Angels May 18-20 and have won just four series this season. They are 3-2 so far on a 10-day, nine-game trek and will visit Oakland for three games this weekend.

San Diego is still last in the NL West at 17 1/2 games off the pace and hope Edinson Volquez can trim the deficit when he takes the mound this evening. Volquez has been struggling lately, going 0-4 with a 5.86 earned run average in his last five starts -- all San Diego defeats. He pitched in Friday's 9-5 loss at Milwaukee and allowed six runs and six hits, including three homers, through five innings.

Volquez is in his first season with the Friars and owns a 2-6 mark in 13 starts to go along with a 3.91 ERA. The right-hander is 1-3 in five road assignments and 1-0 with a 4.24 ERA in four career games (3 starts) against the Mariners.

Seattle has dropped four in a row and will try to avoid losing five straight games for the second time in less than a month. It lost five in a row from May 24-28 and fell to 1-4 on a nine-game homestand last night.

Mariners starter Hector Noesi was solid in defeat and gave up only one run and five hits in seven innings. He just didn't get much offense.

"Offensively, we've just got to figure this out here at home, it's no secret," Mariners manager Eric Wedge said. "We've shown what we're capable of doing on the road and we've just gotta work to help these guys get over the hump here at home."

Jesus Montero had a game-high three hits and Casper Wells ended 2-for-4 for the Mariners, who sit last in the AL West at 10 1/2 games off the pace. The Mariners will welcome San Francisco to Safeco Field for three games this weekend and hope the return of center fielder Franklin Gutierrez will provide a spark. Gutierrez was just activated off the disabled list because of a torn pectoral muscle suffered early in Spring Training and also wrestled a bout of plantar fasciitis in his heel.

A 2010 Gold Glove recipient, Gutierrez is expected to start on Thursday and is excited to get back to work.

"I feel great. I feel happy," Gutierrez said on the ballclub's website. "Finally I'm back and healthy. I feel like the first time I got called up. It's so exciting to be here again."

Gutierrez batted .211 in 10 rehab games in Triple-A Tacoma.

Seattle will pin pitching duties on rookie Erasmo Ramirez this evening. He has made seven relief appearances this season, going 0-0 with a 2.45 earned run average through 11 innings. He will make his first career start and is the youngest player to make an Opening Day roster this season at 22. The right- hander was 3-2 with a 3.11 ERA in seven starts for Triple-A Tacoma.

Ramirez hasn't been with the big league club since May 2.

Seattle won five of six from the Padres a year ago.