MILWAUKEE -- Chris Volstad isn't getting any margin for error during his starts. So when he has one bad inning, it hurts him. It's happened each start, including on Saturday, when he gave up five runs in the Brewers' sixth.

"Right now for him, he's not getting any run support and every pitch is magnified," Cubs pitching coach Chris Bosio said of the right-hander, who is 0-5 in seven starts. "As a staff, we need to have plays made behind us. Yesterday, he did a poor job of trying to execute the pitch in an 0-1 count [to Edwin Maysonet], and the ball cut a little bit and a light-hitting Triple-A guy hits the ball down the line for a grand slam."

Maysonet's grand slam was his second career home run, and carried the Brewers to an 8-2 victory over the Cubs. Volstad is now winless in his last 18 starts, dating back to last July.

The Cubs won't skip Volstad in the rotation, and he is scheduled to make his next start on Thursday when the team returns home to face the Phillies. One option the Cubs have is to move Casey Coleman into Volstad's spot in the rotation. Coleman was added to the roster on Saturday when Carlos Marmol was placed on the disabled list.

"How do you fix [Volstad] is the million-dollar question," Cubs manager Dale Sveum said on Sunday.

The Cubs have made some changes in Volstad's delivery to try and avoid those big innings.

"He was pitching beautiful baseball again [for five innings] and he's shown flashes of that in every start this year," Bosio said. "That's the hard part about the season, is trying to get that one [win] to get you over the hump. [Ryan] Dempster has been in the same situation, too. We just haven't been able to give him any breathing room at all. Being able to pitch and relax a little bit and get some wiggle room, that's huge."

Dempster is winless in five starts, despite boasting a Major League-leading 1.02 ERA. Bosio knows all about dealing with failure.

"I had nine complete games one season and lost six of them on shutouts," Bosio said. "The best advice I got was from Pete Vukovich, who said you have to learn how to win those 1-0 games. That's the same message I'll give these guys. Don't think you have to throw a shutout, think you have to win every at-bat. If you win every at-bat, the chances of you being successful will be better at the end."

Stewart hits a homer with special pink bat

MILWAUKEE -- Cubs third baseman Ian Stewart wrote his mother's name, his wife's name and his mother-in-law's name on his pink wristband on Sunday in honor of Mother's Day, and then hit a solo home run to celebrate.

"It makes it even better on Mother's Day that your mom's watching, and my wife's probably watching and my wife's mom is probably watching," said Stewart, who ended an 0-for-16 skid with a solo homer in the Cubs' 8-2 win over the Brewers. "That was cool."

The third baseman was one of four players who used pink Louisville Slugger bats as part of Major League Baseball's effort to raise awareness of breast cancer. Each team also designated an Honorary Bat Girl, and Kaitlon Busser, a Cubs fan picked as the team's honoree, will be celebrated at an upcoming home game.

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The Cubs players wore pink wristbands and third-base coach Pat Listach had pink shoes. His wife, Cari, is a breast cancer survivor.

Players reminded each other in the clubhouse pregame to call their mothers on Sunday. Rookie Adrian Cardenas didn't need to send flowers to his mom. He was going to send his Mother's Day bats to her.

Bryan LaHair was 0-for-4 with a walk with his pink bat. His used bat will likely be auctioned for charity, and he'll send a clean bat home to his mother.

"I must have picked the wrong one," LaHair said. "The other one probably had a 4-for-4 [day] in it."

Soriano switches to a lighter bat

MILWAUKEE -- Alfonso Soriano has switched to a lighter bat in hopes of ending what is the longest home run drought to start a season in his career.

The Cubs left fielder, who has averaged nearly 32 home runs the last 10 seasons, hasn't hit one over a fence in 112 at-bats. He's had longer homer-less stretches -- 184 at-bats in 2001, for example -- but this is the longest to open a season.

"Edwin Maysonet has more home runs than Alfonso Soriano right now -- that's tough to swallow," Cubs manager Dale Sveum said of the Brewers' second baseman, who has one homer, and two in his career. "We have to get some two- and three-run home runs out of that position, no question about it. We're having trouble sustaining innings enough."

Soriano led the Cubs with six home runs this spring and is healthy, except for his left knee, which is a little tender. One suggestion Sveum and others have made is to try and get the veteran to switch to a lighter bat, which he did about two weeks ago.

"There's no question I'd like to see a much lighter bat," Sveum said on Sunday. "He has adjusted a little bit but a smaller, lighter bat would help a lot."

Soriano said he can tell the difference.

"It makes sense," Soriano said. "I feel more comfortable. I can get the bat through the zone more quickly.

"I've been using the bat for the last two weeks. Sometimes in this game you're feeling good, sometimes you're feeling bad. I think I found my swing today and I hope I can keep it the rest of the season."

On Sunday, he was 1-for-4 with an RBI double in the eighth.

Sveum said hitters can tell when the change is very slight.

"You're talking a few ounces -- two, three ounces," Sveum said. "A shorter bat only makes sense to help out, no question.

"It's almost like mechanics. It's hard to change mechanics and hard to change something that has felt so comfortable to you. Sometimes when you get to a 35 1/2-inch bat and make it 34, just looking at it, it looks like it's 31 inches, it's so much smaller looking. Those are harder things to get over than people think."

More work is better for Camp

MILWAUKEE -- Shawn Camp hasn't pitched in every Cubs game. It just seems that way.

"I'm a sinkerball pitcher and I'm not like a power pitcher," Camp said. "I don't want to say my arm never gets tired. But I feel sometimes, when you're a sinkerball pitcher, the more tired and fatigued you get, the less effort you put into pitches and your sinker gets a little better at times."

He is diligent about following a pregame workout routine that he developed and adjusted with the help of Cubs strength coach Tim Buss.

"You just have to take care of your body, take care of yourself," he said. "Anything I can do to help the team, it's important to me."

Camp said he pitched in seven straight games in 2006 with the Rays, and took more time off than usual after the season ended. But when he reported to Spring Training the next year, he didn't feel right. That's why he's stuck to the extra work. Maybe more is better?

He has told Cubs bullpen coach Lester Strode to keep an eye on him.

"I told [Strode] about a week ago, 'Hey man, if I'm starting to throw too much and you feel I am, just step in front of me, and I won't take offense,'" Camp said.

Has Strode had to do that?

"Once or twice," Camp said, smiling.

Extra bases

• Rookie reliever Rafael Dolis had some minor back problems on Friday, but was able to pitch through it. He was available Sunday, Cubs manager Dale Sveum said.

Dolis, who has taken over the closer's duties, had some difficulty bending down, Sveum said.

• The Cubs head to St. Louis for a quick two-game series on Monday and Tuesday against the first-place Cardinals.

"Obviously, they're the best team in the league, so we're going to have to shut them down," Sveum said. "They've got an American League offense right now. [Carlos] Beltran is on fire. They've penciled [Allen] Craig in from the [disabled list] and he's hit four, five home runs. You really have to keep those guys in the ballpark, and it's tough to keep them down."

The Cardinals lead the National League with 44 home runs; the Cubs have 19.

• Adrian Cardenas collected his first big league hit with a double on Saturday. He got the ball authenticated, as well as the lineup card from the game.

"I feel like I play for the Cubs now," Cardenas said.