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5/1/2014 1:24 A.M. ET

After slow start, Castro warming up at the plate

HOUSTON -- After a slow start at the plate, All-Star catcher Jason Castro ended April with a flourish. Castro was hitting .271 (16-for-59) in his last 16 games prior to Wednesday, with three homers, 10 RBIs and a .889 OPS.

Castro began play Wednesday hitting .228 and tied for the team lead in homers (four) and leading the club in RBIs (13) and on-base percentage (.340) while riding a six-game hitting streak.

"It seems like every year to start, I'm a little slow, and I think it has to do with some timing stuff," he said. "Usually, guys with leg kicks and things like that, they take more time to get comfortable with timing and fine-tuning that aspect of it. I feel really good.

"For the past week and a half or so, I've felt pretty locked it. It probably started in Seattle [last week], so I'm really happy with where I'm at and continue to move forward and kind of fine-tune things when they get off a little bit. I feel like I've reached a point where I'm comfortable in the box and I have a good feel for where I want to be."

Castro began the season with just two hits in his first 20 at-bats. He struck out all three times he stepped to plate in Wednesday's 7-0 loss to end his hitting streak.

Peacock, Keuchel and McHugh to face Mariners

HOUSTON -- The Astros set their rotation for the weekend series against the Mariners at Minute Maid Park, giving right-hander Collin McHugh another start, which was expected after he went 2-0 with a 0.59 ERA in his first two starts.

McHugh, who will start Sunday's series finale, was called up to replace Scott Feldman when he went on the disabled list, and has been dazzling. Brad Peacock will start Friday, and left-hander Dallas Keuchel on Saturday.

Astros manager Bo Porter said Feldman needs just a little more time. He's been on the disabled list for more than a week with biceps tendinitis.

"We just felt like Feldman's had a lot of time off and we want to give him a couple of extra days to continue to get built up, and we'll slot him back in accordingly," Porter said. "We didn't want to slot him in Saturday. We want to let these guys take another turn through."

Feldman is going to throw a simulated game on Sunday, which should be his final hurdle before returning to the rotation. Signed to a three-year, $30 million deal, he went 2-1 with a 1.69 ERA in his first three starts before getting injured.

Struggling Krauss gives way to Guzman

HOUSTON -- Marc Krauss, who had been starting at first base against right-handed pitchers, was on the bench to start Wednesday's game, with Jesus Guzman getting a rare start against a right-hander.

Astros manager Bo Porter said it was simply a case of wanting Guzman in the lineup to face a fastball pitcher in Washington's Jordan Zimmermann, but he wasn't ready to say he was putting an end to the Guzman-Krauss platoon.

"It all depends on the matchups and who we're playing against," he said. "Zimmermann is predominantly a fastball pitcher, and Guzman is a really good fastball hitter."

But it can't be ignored that Krauss is mired in an 0-for-12 slump that has dropped his batting average to .120.

"Right now, he's had some pitches to hit that he hasn't hit," Porter said. "If you miss your pitch, now you're constantly having to deal with hitting the pitcher's pitches, and that makes it more difficult."

Guzman went 3-for-4 with a double in the Astros' 7-0 loss.

Qualls laughs off former teammate Frandsen's bunt

HOUSTON -- Astros reliever Chad Qualls couldn't help but chuckle when Nationals outfielder Kevin Frandsen dropped down a bunt with two outs in the eighth inning Tuesday. Frandsen placed the bunt perfectly for a single -- his first hit off Qualls in three career at-bats.

The hit loaded the bases, but Qualls struck out Jose Lobaton out to end the inning.

"I was in camp with him in Philadelphia and I've played against him for a while and I know him," Qualls said. "I wanted to get out of the inning so I could yell at him at first base. When I got Lobaton out, I looked over at him and went, 'Really? Bunting?' His remark was, 'Dude, I'm 0-for-life off you.' I guess his best chance for a hit was dropping down a bunt.

"That's what he wanted to do. He didn't want to drive in the winning run. He wanted to pass the hat for the next guy, and fortunately I got Lobaton out. Now, he can't say he's 0-for-life off me; he's 1-for-life. Maybe next time he'll swing it."

Frandsen acknowledged his struggles against Qualls and wanted to take advantage of third baseman Matt Dominguez playing deep.

"Against Qualls, I'm probably 0-for-whatever and that foul ball was the hardest thing I'd ever hit against him," he said. "My odds weren't good just swinging away, so I laid one down."

Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.