MILWAUKEE -- Nyjer Morgan was his usual smiling self on Monday, though he was admittedly frustrated on the inside.

The emotional sparkplug of last year's National League Central champs was left out of the Brewers' starting lineup amid a season-opening slump. Morgan entered the night with five singles in 42 at-bats, for a .119 batting average, on-base percentage and slugging percentage. He had one hit in his last 22 at-bats.

"I've got a bad case of the coldness," Morgan said. "I've just got to battle out of it."

This is uncharted territory for Morgan, at least since he joined the Brewers in a trade last March. He said he feels good in the batter's box, and has studied video for reassurance that he has not been swinging at pitches outside the strike zone.

The hits just aren't falling.

"It's frustrating. It's very frustrating," Morgan said. "You just have to keep grinding. ... It's a weird spell, man. I guess last year the spell would have been my injuries at this time of year. Even though I came out on fire, I got injured and I was out a month. That was my funk.

"Knowing me, I always start off [lousy] in April and then always progress. But I've never been through a spell like this. I have to hang in there. ... You have to still show up, same attitude, even though you're a little bit frustrated. You can't let that frustration go off and pile onto the next man. You don't want the next man to feel what you're feeling. You want to be a great teammate and be supportive of these guys."

Morgan said he understood manager Ron Roenicke's decision to start Norichika Aoki in center field. Aoki entered the night 5-for-15 in two starts plus pinch-hit appearances.

"If the right pieces are clicking, you have to put the right pieces in. It's a business, too," Morgan said.

Roenicke characterized the Aoki start as a temporary move. Morgan could be back in the two-hole on Tuesday night against Astros right-hander Bud Norris. Astros left-hander J.A. Happ starts Wednesday, so the Brewers will go with Carlos Gomez, and Roenicke suggested that, given Gomez's hot start to the season, he could see more action against right-handed pitchers in the coming days.

"That's the one position we can play with a little bit because I like all three guys," Roenicke said. "We need to get Nyjer going, that's what we need to do. And before the season's out, he's going to be important to what we do. ... It's two weeks into the season. I don't want to give up on a guy that was really good for us last year. The reason we won was a lot because of him. I don't want to forget that because of two to three weeks of not swinging the bat well."

Roenicke not considering lineup changes

MILWAUKEE -- Internet message boards and sports talk radio was filled Monday with suggestions -- demands, really -- for Brewers manager Ron Roenicke, whose club started the season in a team-wide slump.

Sixteen games into the season, everybody wants dramatic changes to the lineup. Roenicke is resisting.

"You put so much time into why [a lineup] should work, that to change it is saying that all of the stuff you thought made sense doesn't make sense anymore," Roencke said. "That's kind of crazy.

"Sometimes you [change the lineup] just to do it, because you do something crazy. But it's set the way it should be set."

Roenicke has considered moving catcher Jonathan Lucroy up from the eight-hole. He's also considered a favorite move of many fans -- flipping leadoff man Rickie Weeks and two-hole hitter Nyjer Morgan/Norichika Aoki/Carlos Gomez. He doesn't like either idea at the moment.

"I'm not going to ask Rickie to start bunting, to start hitting and running," Roenicke said, "so I don't know if that really makes sense, either."

He added: "When things make sense, that's when we do them."

Peralta soaks in first big league outing

MILWAUKEE -- The Brewers gave top prospect Wily Peralta a copy of the lineup card from Sunday's loss to the Rockies, a memento of Peralta's Major League debut. He was excited for the chance to show it off to family and friends in the Dominican Republic.

That will have to wait, because there's plenty of season left. Peralta was optioned back to Triple-A Nashville on Monday after the Brewers beat the Astros, 6-5, clearing room for reliever Kameron Loe to return from the bereavement list in time for Game 2 of the series on Tuesday. Peralta is now Milwaukee's top option should something happen to a member of the starting rotation.

"It was great, the first day being on the Major League mound," Peralta said. "When you start playing baseball, you think about being a big league pitcher. I wasn't nervous."

The Brewers have already needed one replacement for the rotation. Marco Estrada moved up to replace left-hander Chris Narveson, who was waiting for final word Monday about whether he'd need surgery for a torn rotator cuff.

Peralta pitched the ninth inning against the Rockies with the Brewers trailing, 3-1, and surrendered a run on three hits. He pitched mostly with his fastball, which touched 97 mph on strike three to Tyler Colvin, Peralta's first Major League strikeout victim.

"That was nice," manager Ron Roenicke said. "He [also] threw a couple of nice breaking balls. But it's just getting over the nerves, and he'll be fine."

Peralta is listed as Nashville's probable starter for Thursday.

Last call

• Brewers head athletic trainer Dan Wright celebrated his 50th birthday on Monday. The hard-working Wright has an expanded role this season after his old boss, Roger Caplinger, was promoted to director of medical operations.

• Tickets remain for Friday's Minor League game at Miller Park between the Class A Wisconsin Timber Rattlers and the Dayton Dragons. Reserved seats are $10 each and hot dogs and sodas will be priced at just $1 apiece. For full details, see the special section of Brewers.com dedicated to the annual event.