The Mariners have won 10 of their last 12 games, taking two of three from the Detroit Tigers over the weekend. Their 8-1 win on Sunday put them a half-game ahead of the Tigers for the second wild card spot in the American League.
Chris Young helped put his club back into a playoff spot with six scoreless innings, matching a career high with his 12th win of the season.
"This is a very tough lineup and he did an extremely good job. He gave us six solid innings," Mariners manager Lloyd McClendon said of Young.
Kyle Seager knocked in three runs, Chris Denorfia had an RBI triple among his three hits and Robinson Cano scored three times for Seattle.
Rookie Roenis Elias will return to the Mariners rotation tonight.
Elias has not pitched with Seattle since Aug. 7 as the club did not need a fifth starter until tonight. Instead, the 26-year-old southpaw made a short outing on Wednesday with Triple-A Tacoma and it was a good one, with Elias throwing five no-hit innings.
Elias has been very solid at the back end of the rotation for Seattle, going 9-9 with a 4.14 earned run average. He will face the Phillies for the first time.
Jerome Williams will make his second start tonight for the Phils since being claimed off waivers. He was 2-5 with a 6.71 ERA in 28 games (2 starts) this season with Texas and Houston, but pitched well in a no-decision versus the Los Angeles Angels of Anaheim on Tuesday.
Williams held the Angels to a pair of runs over 5 1/3 innings, working around five hits and one walk, but the Philadelphia bullpen struggled in an eventual 7-2 setback.
"Jerome did a nice job. He showed his experience, hitting his spots with his fastball," Phillies manager Ryne Sandberg said. "We just couldn't finish out the sixth inning."
The 32-year-old righty is 5-2 with a 3.58 ERA in 15 career meetings with Seattle, including seven starts.
The Phillies have lost seven of nine and are coming off a 5-2 setback to the San Francisco Giants on Sunday.
Cody Asche and Ben Revere both had three hits, with Revere upping his batting average to .314. That is the second-best average in the National League, trailing only the .323 mark of Colorado's Justin Morneau.
The Mariners have won seven of nine versus the Phillies dating back to 2003, when they swept the club in three games in their only previous trip to Philadelphia.