HOUSTON -- Astros outfielder Kyle Tucker knows better than anyone how unpredictable fly balls hit to right field can be at Minute Maid Park. It was earlier this month, while playing the Red Sox, when Tucker skied a fly ball to right that Boston’s Alex Verdugo climbed the wall to chase before retreating and catching while standing on the track with ease.

So when he lofted a slider from A’s lefty reliever Sam Moll high into the sky with the bases loaded in the fifth inning Friday, he really wasn’t sure what to expect as A’s right fielder Chad Pinder approached the wall. 

“I hit it pretty well and I was like, ‘All right, sweet,’” Tucker said. “Then I was thinking back [to] when Verdugo went over there and did that and I flew out. I was like, ‘Please let it go over.’ But luckily, it went over and we took the lead from there and kept it.”

The ball landed in about the third row in right field, giving Tucker his second grand slam of the season and giving the Astros the lead. Tucker also threw out a runner at second base and was instrumental in Houston’s 7-5 win over Oakland, which pushed the Astros 1 1/2 games ahead of the Yankees for best record in the American League.

“Our momentum started rolling that inning, and the crowd got into it,” Astros manager Dusty Baker said of the homer. “Boy, that was huge.” 

After missing four games in Cleveland last week (with the exception of a pinch-hit appearance) because he was ill, Tucker has returned to the lineup and gone 7-for-16 (.438) with two homers and seven RBIs in four games. The grand slam was the third of his career and his first since May 17 against the Red Sox. 

The tail of the tape of the grand slam wasn’t eye-popping. The ball left his bat at 99.6 mph and traveled 356 feet. Regardless, it was enough to give the Astros a 5-2 lead.

“It was like a slider up,” Tucker said. “I’m sure he’d rather not throw it there, but luckily for us, I was able to get that pitch and hit it out. It worked out well for us.” 

Tucker did crush a pitch two innings later, but had nothing to show for it. He hit a rocket to right-center field, only to watch center fielder Skye Bolt run it down. The ball came off his bat at 104.6 mph and traveled 408 feet … for an out. 

“I hit it pretty well, and it’s pretty deep out there to center,” Tucker said. “I don’t think I have a ball hit out to center here. I’ve got to work out a little bit more. I hit it well. I can’t do much more than that.”

Tucker has sought out advice from slugger Yordan Alvarez, who routinely hits balls out at center field at Minute Maid Park, about what little bit extra he needs to do it, as well. 

“Every time I do that, I go up to Yordan, because Yordan launches balls over the batter’s eye and stuff and I’m just like, ‘I can’t do it like you,’” Tucker said. “We have a little joke about that. I’ve got to get a little stronger, I guess.”

Alvarez, who’s a left-handed hitter, was one of the Astros on base for Tucker’s homer. The A’s brought on a lefty, Moll, to face Alvarez, who singled to right. Moll walked Alex Bregman before Tucker, also a lefty, took him deep. The lefty-on-lefty move backfired. 

“They’ve got a bunch of lefties out of the ‘pen,” Tucker said. “We’re always in a close game or something, where you kind of expect they’re going to bring up their lefties. We don’t mind facing righties or lefties. [We both have] very good hitters. We just try to put together a good at-bat and try and win it.”

Earlier in the fifth, Tucker tracked down a single off the bat off former teammate Tony Kemp in deep right field and whirled and threw him out at second base, with shortstop Jeremy Peña applying a nice tag. 

“I just happened to throw it right there, and Peña had a great tag,” Tucker said. “It worked out well for us.” 

Especially for starting pitcher Luis Garcia. 

“It was huge,” Garcia said. “I’m really happy for that. He did an awesome job, and then he hit a freaking bomb.”