SAN DIEGO -- The final inning of Framber Valdez’s start on Saturday against the Padres was a noticeable turnaround compared with how the 27-year-old began his night.

With 16 pitches, Valdez retired the Padres in order in the sixth inning of the Astros’ 10-2 loss at Petco Park. The frame capped off a string of four straight scoreless innings for Valdez.

• Box score

In Valdez’s second inning of work, however, the left-hander gave up four runs and four hits, hit two batters and balked in a run during a 29-pitch inning. An early 2-0 lead, built on an RBI single from Yuli Gurriel and a solo homer from Kyle Tucker, was wiped away as Valdez struggled to find his composure.

“I think things got out of control just a little bit there in the second inning, and I just tried to limit the damage as much as possible,” Valdez said. “[I was] just trying to execute my pitches, and I was able to get out of that situation with just the four runs and then was able to limit it from there. It's just a matter of trying to execute my pitches to get out of that situation.”

During the second inning, Valdez hit Adam Frazier on the helmet with a pitch that he said slipped away from him. Frazier was the second batter to reach base in the inning, after Wil Myers doubled with one out.

Valdez said the pitch was not intentional and it was something he had trouble shaking off in the inning.

“I felt a little bit bothered by that situation just because I'm not used to that pitch getting away [and] out of my control as much as it did,” Valdez said. “I don't want them to think there's any kind of intent behind that because there definitely wasn't. … I was thinking about it a little bit in the next [at-bat], and that's when things got a little bit out of control.”

The Astros remain 5 1/2 games up in the American League West, with Oakland and Seattle now co-tenants in second place.

Manager Dusty Baker said part of Valdez’s struggles came on solid execution by the Padres right-handed hitters to hit the ball to the opposite field.

Valdez gave up three opposite-field hits to the Padres right-handed hitters in the second inning, but limited the Padres to only two hits over his next four innings: a single by Frazier and an infield single by opposing pitcher Joe Musgrove.

Baker said the adjustments past the second inning came from Valdez’s ability to work the inside part of the strike zone.

“They caused it," Baker said of the second-inning damage. “I could tell their game plan against [Valdez] was to try to hit him to right field. All the right-handed hitters are trying to hit that hole over there, and they finally hit it, especially Tatis. Tatis did it the first at-bat, and so did Machado. ... That was their game plan, and that was a pretty good game plan. And then he made the adjustment.”

One night after Houston used eight pitchers in a 6-3 win over San Diego -- its most pitchers used in a nine-inning win since Sept. 25, 2006 -- Valdez managed to keep the Astros within two runs until his night came to a close.

The Padres broke the game open with two two-run homers off Cristian Javier in the seventh inning and another two-run homer off Josh James in the eighth inning.

“[Valdez’s] pitch count wasn't that high, [and] we were still in that ballgame at that time,” Baker said. “It was 4-2 when he went out there [in the third inning]. We just simply can't go five innings every night because that's going to put a tremendous amount of stress on my bullpen, and I didn't have certain guys tonight. … We tried to take him as far as we could and not burn up all of our bullpen.”