(SportsNetwork.com) - The Seattle Mariners hope to get a third straight winning start tonight out of right- hander Hisashi Iwakuma in the finale of a three-game series with the Houston Astros.

Iwakuma is 5-0 with a 3.06 earned run average over his last six starts and won his second straight outing on Friday as he held Texas to three runs on seven hits and a walk in 5 1/3 innings. That improved him to 14-6 on the year with a 2.97 ERA.

The 33-year-old is 4-2 with a 2.56 ERA in seven career meetings with Houston.

The Astros are planning on going with a six-man rotation to close out the season, so right-hander Nick Tropeano will make his major league debut tonight.

The 24-year-old joins the big league club after a solid season at Triple-A Oklahoma City, going 9-5 with a 3.03 ERA in 23 games with 20 starts. He also struck out 120 over his 124 2/3 innings while getting selected to the Pacific Coast League All-Star Game.

"It's a great experience," general manager Jeff Luhnow told Houston's website. "He pitched a full year, so he doesn't need a lot of innings. We need to be careful not to overuse him. We do want to see how he performs against big league hitting. It's an exciting opportunity for him, and it gives our guys a little bit of a breather."

Houston snapped a four-game slide to Seattle with a 2-1 victory on Tuesday. Jonathan Villar hit a go-ahead RBI single in the top of the ninth off Mariners reliever Yoervis Medina.

Medina yielded a two-out walk to Jon Singleton and then unleashed a wild pitch before giving up an infield single to Matt Dominguez. Villar then bounced one past the glove of second baseman Robinson Cano to plate Singleton.

"It was one of those nights for him, he just didn't have his stuff," Mariners manager Lloyd McClendon said of Medina.

Collin McHugh allowed a run on just two hits with four strikeouts over eight innings for Houston, which won for the seventh time in nine games.

"He's got three good pitches," said Astros interim manager Tom Lawless. "When he's around the plate, he's pretty hard to hit."

Seattle managed only two hits in last night's game, a single by Austin Jackson in the fourth inning and Logan Morrison's game-tying homer in the eighth.

The Mariners, though, lost for the third time in 10 games and sit a half-game back of the American League's second wild card spot.

Seattle is 9-6 versus Houston this year.