HOUSTON -- Brandon Pfaadt was unable to get through the fifth inning and Arizona’s offense could not get much going in an 8-0 loss to the Astros on Friday night at Minute Maid Park.

Arizona’s chances in the NL West continued to shrink with the loss, and its lead for the second NL Wild Card spot was cut to 1 1/2 games over the Braves and Mets, who both won Friday. The D-backs remained 5 1/2 games back in the West, as the Dodgers lost to Cleveland.

Pfaadt allowed four runs on eight hits with five strikeouts in 4 2/3 innings. It was his fifth straight start allowing at least three runs.

"I think there’s more good than it seems,” Pfaadt said. “I think we made some good pitches at times. I got out of some jams. I think the problem was we had some early traffic. I think that’s why the lineup turned over, and Yordan [Alvarez] came up in a big spot in the fifth and did some damage."

Arizona manager Torey Lovullo said it was not a "typical" outing from his young right-hander.

"I thought he had some good moments,” Lovullo said. “He was following the game plan and driving his fastball into the zone, which I think is very important to him, the two-seam and the four-seam. But there were just some mistakes. … There were some misses out over the plate, and clearly, the big blow was the home run by Alvarez.

"I think he was trying to make adjustments, just couldn’t find it," Lovullo added. "He never really got into a rhythm. That wasn’t a typical Brandon outing. He really gets moving in a very positive direction. There was one inning in there, I think it was the fourth, where he was flushing it really good. That’s normally what he gives us, but he never really got into a rhythm today.”

Pfaadt faced a lot of traffic most of his outing, as the Astros had runners in scoring position in the first, second, third and fifth innings.

“It was really tough,” said catcher Jose Herrera, who exited for precautionary reasons after getting hit in the helmet with a backswing in the fifth but was deemed OK. “We would get ahead of guys, but we couldn’t put them away. It was really hard to find the rhythm to get him through the game, but he’s a grinder. He goes out there and gives you 100%."

The Astros scored a run in the second, but it could have been more as Corbin Carroll and Geraldo Perdomo teamed up to cut down Jon Singleton at the plate as he tried to score on a Ben Gamel double.

"Those are very pleasing to me,” Lovullo said. “Everyone is lined up the right way. Our outfielders do a really good job of taking direct lines to the ball and cutting balls off, saving distance and getting them to the cutoff man. That’s what I want to do here. I want to get the ball into the infielder’s hands as quickly as possible so they can make plays like Gerry made. It was a strike one-hop with a great tag and got us out of a little bit of a situation.”

Alvarez hit a three-run homer off Pfaadt in the fifth, and added another three-run homer in the sixth off Jordan Montgomery to put the game out of reach.

The Diamondbacks didn’t have many opportunities against Houston’s Framber Valdez. Perdomo hit an infield single off the left-hander in the third, but he was tagged out trying to go from second to third on Ketel Marte’s groundout to third.

"I think when you have these small opportunities, you get into a little bit of a force mentality,” Lovullo said of Perdomo. “He knows you can’t run into an out there. You’ve got to make the third baseman throw it across the diamond. Once he committed to it, I think he knew he made a mistake, and he couldn’t turn back. You want to keep the man in scoring position there."

Marte, who was activated Friday after missing three weeks with a sprained left ankle, did not provide much offensive support, going 0-for-3 with a walk. Carroll was 0-for-4 and saw his franchise-record 44-game on-base streak in starts come to an end.