HOUSTON -- Jeremy Peña remains an early American League Rookie of the Year frontrunner, with the Astros' shortstop ranking first among AL rookies in WAR, home runs, slugging and OPS entering Saturday. 

But for perhaps the first time in his young Major League career, the 24-year-old is going through a slump, and it has proven costly on this homestand at Minute Maid Park. 

Peña made a crucial second-inning error that led to the Marlins scoring three runs (two unearned), and Miami was in control from that point forward in Houston's 5-1 loss on Saturday afternoon. The Astros (36-23) have now lost three straight and are 1-4 on this homestand, though they still lead the AL West by a comfortable margin of 8.5 games.

Though Peña made only one error, Houston’s normally reliable shortstop had two other balls hit to him in that same frame that he was also unable to turn into outs. Combine that with two ill-timed walks by Astros starter Framber Valdez, and the Marlins (27-30) scored three runs in the inning without hitting any ball directly to the outfield.

“I just misplayed them,” Peña said. “We're not executing right now as well as we should be. We learn from it, and keep going.” 

“Those were tough balls,” Astros manager Dusty Baker said. “When it hits that [dirt] part of the infield first, and the grass doesn't take any steam out of it, that ball was hit pretty good. Those were tough plays, and a lot of times, they seem to find you in a short period of time. The ball wasn't really bouncing our way, and it hasn't bounced our way in a while.”

In all, Valdez gave up four runs (two earned) and four hits in six innings. He struck out six but issued three costly walks. It added up to the second-most runs that Valdez has allowed in any game this season. Entering Saturday, Houston's young left-hander had turned in eight consecutive quality starts.

At the plate, Houston’s early-season offensive struggles continued, with the home team unable to muster a consistent threat against Marlins starter Braxton Garrett. After allowing four runs in 3 1/3 innings during his last start on June 5, the 24-year-old right-hander gave up six hits and only one unearned run in 5 2/3 innings on Saturday.

With big names like Alex Bregman and Yuli Gurriel off to sluggish starts, an early surge by Peña had helped the Astros overcome some of those other struggles in April and May as Houston built a large division lead. But in June, Peña has fallen off the pace, and the other Astros haven’t yet picked up the slack. For the month, Peña now has a .536 OPS, significantly lower than his figures of .872 in May and .763 in April.  

“Just relax and play, and be as natural as possible,” Baker said of his advice for Peña. “Learn from the situation. It's going to pop up again, but once it does, you know how to deal with it in the future.”

“I love the way he's playing,” Jose Altuve said of Peña. “He's going 100 percent. Great kid. Tomorrow is another day.” 

On Saturday, Peña went 0-for-4, including a strikeout with two runners in scoring position (RISP) to end the sixth inning. Houston’s only bigger opportunity to rally came after loading the bases with no outs in the seventh, but it failed to score after Michael Brantley struck out swinging and Bregman lined into a double play.

“It starts with me,” Bregman said. “I had back-to-back days with the bases loaded and didn't come through. "Guys have done a great job getting on base, and it comes down to driving guys in when they're out there. I haven't done a good job of that. 

“I've struggled before in this game, and the only thing you can do is work at it and keep going. I need to be better, and I will be better."

The good news for the Astros, as they look to avoid a sweep in Sunday’s series finale, is that they have their ace, Justin Verlander, in line to start. But for a sustained turnaround, the defending American League champions need more offense. 

“We’ve got to fight through this,” said Baker, whose offense hit 1-for-13 with RISP after going 2-for-16 in Friday’s loss. “Every team is going to go through it. This team doesn't like to lose, so they're going to be frustrated. Guys are used to winning, and used to coming through [with men on base]. They're going to come through again, shortly.”