May 27—SEATTLE — Jon Singleton swung and the sound portended promise. The baseball left his bat at 103.4 mph but arced toward the depths of T-Mobile Park’s center field. Julio Rodríguez settled under it and secured a routine out to end the sixth inning, stranding the potential tying run of a pitching duel on third base.“I hit it pretty well,” Singleton said. “With two strikes, you just hope to flush a ball like that. Just a tough day.”It proved the closest the Astros came to erasing an early deficit they could not surmount Monday night in Seattle. Three Mariners relievers followed with scoreless innings to hand them a 3-2 loss in the opener of a four-game series that widened Houston’s gap in the AL West.The Astros fell to 24-30 and 4 1/2 games behind Seattle in the division. Their offense was quiet outside of a two-run fifth inning. They totaled six hits, as did the Mariners, and were 2-for-5 with runners in scoring position.Houston faced a 3-0 deficit after one inning. Starter Framber Valdez surrendered four hits in the first to a Mariners team that tagged him for five runs in Houston earlier this month. Valdez needed 25 pitches to notch his first three outs. He navigated two more singles in a scoreless second.“I just thought that it took him a little bit of time for his sinker to be down and to execute,” manager Joe Espada said. “He just wasn’t executing his pitches like he wanted to. Then after that, he settled and he threw a heck of a game.”Valdez threw four more innings without allowing another hit, settling in to give the Astros a quality start. A ground out by Mitch Garver to end the second began a stretch of 11 straight hitters retired by the left-hander. It ended with a one-out walk to Ty France in the sixth.Valdez unleashed two wild pitches and issued a two-out walk to Ryan Bliss, the Mariners second baseman making his major-league debut. With his bullpen active, Valdez induced a ground ball from Jonatan Clase to end the sixth on his 96th pitch.“Just tried to control my pitches, throw strikes and try to keep the ball low and be focused,” Valdez said through an interpreter.He still exited with Houston in a deficit. Seattle starter Bryce Miller allowed two runs in six innings, both scoring in the fifth. Miller retired 13 of his ...