The Houston Astros are hoping the road trip they're about to begin will last longer than six games.

They have a slender lead for the AL's second wild card and still harbor AL West title hopes as they open a three-game series Monday night against the Seattle Mariners.

Houston (82-74) is one-half game ahead of the Los Angeles Angels and 1 1/2 in front of Minnesota in the wild-card standings. The Astros trail first-place Texas by 2 1/2 games in the division race.

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This trip through Seattle (74-82) and Arizona will extend if Houston reaches the playoffs. The club told players to bring their passports for a potential visit to East-leading Toronto next week.

The Astros, a major league-best 15-8 on the road through the end of May, are 8-20 away from home since the All-Star break to tie Oakland for baseball's second-worst mark.

"I wish I could explain what's happened," manager A.J. Hinch said. "I'm trying to put myself back in the mind-set in April and May when I was asked why we were so good on the road and why we were bad at home."

Houston closed its home slate with Sunday's 4-2 win over Texas behind Dallas Keuchel, who went 15-0 at Minute Maid Park this year after striking out 10 in seven innings. Jake Marisnick gave Houston the lead for good with a two-run double in the second inning.

"We want to put as much pressure on the Rangers as we can," Hinch said.

Chris Carter has homered in four straight starts. Hinch says he will continue to platoon Carter with the lefty-swinging Luis Valbuena.

Carter figures to be in the lineup for a majority of this series since the Mariners have tabbed lefties Roenis Elias (5-8, 3.94) and Vidal Nuno to start Monday and Tuesday.

"I'd expect to see him play a big role for us this final week," Hinch said. "We've got two lefties to kick off this Mariners series."

Seattle is 2-6 in Elias' home starts, with the southpaw going 2-4 with a 3.86 ERA. He is 1-2 with a 6.65 ERA in four overall outings versus Houston this year.

Elias is 1-2 with a 3.21 ERA in five starts since being recalled Aug. 23 from Triple-A Tacoma. Carter is 1 for 8 against him this year and Evan Gattis 4 for 9 with a homer.

The Astros have dropped the last five starts made by Lance McCullers (5-7, 3.22), who is 0-4 with a 4.70 ERA in his previous seven.

The rookie right-hander is 1-1 with a 2.89 ERA in two starts against Seattle during which he opposed Elias both times. His road ERA is 4.88 compared to .186 at home.

Seattle clinched its fifth losing season in six years with a fifth straight loss, 3-2 to the Los Angeles Angels on Sunday to cap a 3-6 trip.

Perhaps the biggest intrigue on this six-game homestand will be whether Nelson Cruz finishes on top of the majors in homers again. He's tied with Baltimore's Chris Davis for the lead with 43.

The Astros' Carlos Gomez has missed the last 14 games with an intercostal strain, but there's a chance he could return later in this series.