HOUSTON -- Adrián Martínez struggled with his command on Friday night, and it cost him.

Martínez was tagged for four runs on four hits -- all solo home runs -- and Oakland’s offense was quieted by Justin Verlander and Houston’s bullpen in a 5-0 loss to the Astros at Minute Maid Park.

Three of the four home runs he surrendered were massive dingers to Yordan Alvarez, with the other solo blast coming off the bat of Jeremy Peña.

“Obviously for Adrián, take Alvarez out of the lineup, and the line is a lot different,” said A's manager Mark Kotsay. “… Outside of those at-bats, I thought Adrián did a nice job of handling the lineup. He had a few walks mixed in and a few strikeouts. Overall, I still liked the way the ball was coming out and the competitiveness.”

Martínez also struck out six in five innings. The right-hander, who has had an up-and-down season in his four stints with Oakland this season, was coming off an outing in which he gave up seven runs on 14 hits in 3 2/3 innings on Saturday against the White Sox.

“I think for a lot of our young starting pitchers, command is where they get beat,” Kotsay said. “I think that’s in general for pitching. Execution of location at this level is top priority, and we saw that tonight on the other side with a veteran pitcher [in Verlander], who knows how to locate and disrupt timing. Ultimately, as these guys get more time here and get more experience on the mound ... I think they’ve already realized the importance of location.”

Martínez said through an interpreter that he was trying to work on painting the edges of the plate, but he was missing.

“I was struggling,” Martínez said. “I kept missing my pitches, and Alvarez is a great batter. He had a lot of success.”

In total, Martínez now has four starts in which he has allowed four earned runs or more and five starts in which he has yielded three or fewer earned runs.

“Outing by outing, [I’m] making sure that I continue to analyze the batters and focusing on the batters and visualize what I am trying to do,” Martínez said.

The A’s offense sputtered against Verlander, who returned from the injured list and didn’t allow a hit across five innings. Nick Allen singled to break up the no-hitter in the sixth off Phil Maton. Sean Murphy finished with two of Oakland’s three hits.

The night wasn’t all bad for the A’s, as Jared Koenig, who was recalled from Triple-A Las Vegas before the game on Friday, threw three innings and allowed just one run.

“I liked Jared’s mix tonight,” Kotsay said. “He used his curveball; he used his changeup, slider. He pitched in. In terms of him coming here and stepping in, it was his day to start for Vegas, so when we got behind there, it was an opportunity for him to come in and hold the score. I thought over three innings, giving up one run [against the Astros’] lineup, he did a nice job.”

Koenig threw his curveball 44 percent of the time, his sinker 29 percent and changeup 18 percent against the Astros.

“My curveball and changeup were actually really good today,” Koenig said. “My fastball, for the most part, was pretty solid. The curveball and changeup were two solid pitches.”

Koenig was 6-6 with a 4.71 ERA in 20 games (18 starts) for Las Vegas, and he entered Friday 1-3 with a 5.72 ERA in six games (five starts) with Oakland this season.

Koenig said he didn’t get a lot of sleep Thursday night and had an early flight to get from Las Vegas to Houston, but he felt pretty good overall following the outing.

“I was able to come out and basically do my job and hold [the Astros] to one run over three innings, keep the game within reach,” Koenig said.

On a night when Alvarez homered three times, Koenig was happy to prevent a fourth in the seventh, allowing a single instead.

“I was just trying not to give up the fourth,” Koenig said. “I missed a curveball a little in the middle. I needed that a little more away, but I’ll take a ground ball out of that.”

As for what he can take from the outing?

“It just keeps building the confidence that I can come out of the 'pen and get guys out and continue to be successful up here,” Koenig said.