The Padres hope for similar success against the Mariners at Petco Park, where the two begin a three-game series Friday night.San Diego earned its only sweep this season in Seattle last week. Padres starters went 3-0 with a 0.90 ERA, allowing two runs in 20 innings.However, San Diego (24-46) was unable to build on it, losing two of three at Oakland last weekend and getting swept by Texas at home after Wednesday's 4-2 loss.San Diego couldn't protect a 2-1 lead after Anthony Bass exited following the fifth inning with shoulder inflammation. The Padres, who already have five starters among seven pitchers on the disabled list, hope the injury isn't serious."Things are going well, I'm feeling good and then it's like, 'Shoot, you're kidding me,'" Bass told the team's official website.The Padres will hand the ball to Clayton Richard (4-7, 3.94 ERA) as they try to avoid their first six-game home losing streak since 2010 and a fourth straight loss overall.Richard has won his last two starts, both in interleague play. He scattered five hits and struck out six in 7 2/3 scoreless innings in beating Oakland 2-1 on Sunday.Richard's previous start was against Seattle on June 12, limiting the Mariners to one run in seven innings of a 5-4 victory. The left-hander is 4-0 with a 1.35 ERA in his last four starts against the AL and 3-1 with a 1.97 ERA against the Mariners.However, Seattle (30-41) put up big offensive numbers in its last two games at Arizona heading into this series.Though the Mariners rank near the bottom of the majors in batting average, they have scored 10 or more runs in the last two games. It wasn't enough in a 14-10 loss Wednesday.Jason Vargas allowed 10 runs -- surrendering five homers -- in 4 1/3 innings. Franklin Gutierrez hit a three-run shot in the eighth inning -- his first homer of the season -- to make things interesting."That's baseball; they scored more than us," manager Eric Wedge said. "We just had trouble keeping the ball in the ballpark today."Seattle's starters have posted a 7.31 ERA as the Mariners have dropped eight of 11, and their last two starters failed to make it out of the fifth inning.Kevin Millwood (3-5, 3.69) will try to end that trend. He did not get a decision Saturday after giving up four runs and nine hits in five innings of a 7-4 win over the San Francisco Giants.It was Millwood's first start since suffering a slight groin strain in a 1-0 victory over the Los Angeles Dodgers on June 8, throwing the first six innings of a no-hitter finished by five relievers.The right-hander has had good success against the Padres, going 8-2 with a 3.27 ERA, including 4-0 with a 3.30 ERA in San Diego.Carlos Quentin, who is hitting .367 with six homers in 19 games since returning from the disabled list, is 4 for 9 with a homer and two doubles against Millwood.The Mariners have won four straight in San Diego.