Angels not about to panic

That torrid stretch in which the Angels won 17 of 20 games from June 27 to July 22 seemed a distant memory Thursday night as Jason Castro’s walk-off three-run home run sailed into the right-center field seats in Minute Maid Park.

Castro’s shot off Fernando Salas gave the Houston Astros a dramatic 3-0 win over the Angels and sparked a wild celebration at home plate, where Castro tossed his helmet in the air and was mobbed by teammates who doused him with buckets of ice water and ripped the jersey off his back.

It also capped a three-game sweep that, combined with Houston’s trade-deadline acquisitions of pitcher Scott Kazmir, who was dominant Thursday night, and center fielder Carlos Gomez, could shift the balance of power in the American League West, a division the Astros now lead by two games over the Angels.

“To bring a player like Carlos Gomez into our organization in the prime of his career to complement a lot of great players we have now means we’re serious about doing some damage this year and in the years to come,” Astros General Manager Jeff Luhnow said. “It’s going to be a fun next few years for the Astros.”

The Angels aren’t exactly quaking in their cleats. Yes, they’ve lost six of seven games, and the road ahead doesn’t get any easier; they must face dominant Dodgers pitchers Clayton Kershaw on Friday night and Zack Greinke on Saturday.

And, yes, Houston’s moves left Angels fans feeling underwhelmed by the modest upgrades interim GM Bill Stoneman made this week, acquiring veteran outfielders Shane Victorino from Boston, David DeJesus from Tampa Bay and David Murphy from Cleveland to give the Angels platoons in left field and at designated hitter.

But the Angels still have a pair of 30-home run hitters in Mike Trout, who returned from a two-game absence because of a sore left wrist Thursday night, and Albert Pujols, a solid rotation and the experience of winning the division by 10 games last season despite trailing by four games in early August.

“They pitched well in this series, they caught a couple of breaks and beat us, but it’s not like we’re 10 games out,” Pujols said. “This is not the last game of the season. There’s a lot of baseball left, and we have two more series against those guys.”

The Astros coughed up a seven-game division lead by losing seven straight from June 4 to 10 and nine of 11 from July 4 to 18, but now they’re hot, winning nine of 12 since the All-Star break.

“Look, there’s a lot of baseball left,” catcher Chris Iannetta said. “If they can sustain the way they’re playing for the next two months, I’ll tip my cap to them. But there are going to be ups and downs. It’s about getting hot at the right time. Let’s stay within striking distance and see where we’re at in the last month.”

The Angels were within striking distance Thursday, thanks to another dominant start by Matt Shoemaker, who allowed three hits in seven shutout innings, struck out seven and walked one and has pitched to a 2.01 earned-run average in his last six starts.

But Kazmir, acquired from Oakland last week, was just as good, allowing three hits in 72/3 shutout innings, striking out five, walking three and not allowing a runner to reach second until the eighth, when Johnny Giavotella led off with a single and advanced on Taylor Featherston’s bunt.

Kazmir walked Victorino, and both runners advanced on a wild pitch, but Kole Calhoun couldn’t check his swing on a high fastball and struck out. Sidearm-throwing Pat Neshek struck out Trout to end the inning.

“We had a tough week — we didn’t do a lot of the things we’ve been doing,” Manager Mike Scioscia said. “It happens. You’re not going to be firing on all cylinders all the time. We need to regroup and start building momentum again.”

Up next

Left-hander Hector Santiago (7-4, 2.43 ERA) will oppose Dodgers left-hander Clayton Kershaw (8-6, 2.51) at Dodger Stadium on Friday at 7 p.m. TV: FS West, SNLA; Radio: 570, 710, 830, 1020, 1330.

mike.digiovanna@latimes.com

Twitter: @MikeDiGiovanna