ATLANTA -- Cubs manager Dale Sveum wasn't happy with Chris Volstad after Tuesday's 10-3 loss to the Braves, saying he didn't stick to the game plan, but the pitcher said he didn't shake off his catcher that much. It seems that there's a little communication problem.

"I haven't talked to him yet, but I will talk to him," Sveum said Wednesday. "There was a lot of shaking off going on. We'll try to get to the bottom of it."

Volstad took the loss Tuesday, giving up six runs over 4 1/3 innings. He is now winless in his last 20 starts.

"It seems like the same old thing with Chris," Cubs pitching coach Chris Bosio said. "He puts up four or five zeros, and then he starts pressing a little bit."

Volstad gave up one run on three hits over the first four innings, but the first two batters in the fifth each singled, and then he walked pinch-hitter Chris Hinske. Then, it snowballed.

"He said he tried to make a perfect pitch [to Hinske], and he didn't," Bosio said. "He threw some good pitches, and he threw some other pitches that were questionable in certain counts. His tempo was good, and he battled. ... There's still a lot of improvement that needs to happen with Chris, and not only mentally, but physically."

Sveum was upset after the game that Volstad didn't follow their game plan.

"I'll just say we wandered a little bit from what we want to do," Bosio said.

The Cubs have asked their catchers to take an active role with the pitchers.

"We do have a clear game plan, and when we execute our plan, for the most part, we've been in every game," Bosio said. "It's when we deviate or walk guys or don't make pitches [that get us in trouble]. That walk yesterday really hurt us in that inning. A pinch-hitter coming off the bench, a guy like Hinske, will give him a professional at-bat. That was a huge spot there where we needed him to put the ball in play, and we weren't able to do it."

Catcher Steve Clevenger, who was behind the plate Tuesday, must have felt like Crash Davis from the movie "Bull Durham." The rookie was behind the plate Monday and guided Jeff Samardzija through seven solid innings in which he gave up one run and struck out a career-high 11 batters against the Braves.

Dempster targeting Sunday for return to mound

ATLANTA -- The Cubs' Ryan Dempster doesn't want to wait until after the All-Star break to pitch. He may be ready to go Sunday.

After throwing his second bullpen session since going on the disabled list June 16, Dempster said Wednesday he might be ready for the series finale against the Mets, which is the Cubs' last game before the break.

"I think they want to wait until [Thursday] and see how it feels, and then we'll have an idea and an answer," Dempster said. "It's easy to say 'yes' today when you feel great throwing a side. We'll see how it feels tomorrow."

He's been sidelined with a sore right lat and says he feels as if he has his full range of motion and strength back.

"I think they trust me to make the right decisions," Dempster said. "I also don't want to go out there and have a 50-pitch limit, and that doesn't do us any good."

It seems a little rushed, but Cubs manager Dale Sveum didn't dismiss the idea.

"I know he's serious [about it], and we'll give it some thought," Sveum said. "Today's session went great, and we'll probably evaluate him [Thursday] and Friday and make a decision on Friday and see how everything goes the next couple days."

It's been a fairly quick rehab. On Monday, Dempster threw 40 pitches in the bullpen and another 50 on flat ground.

"Not everybody's Ryan Dempster either," Sveum said. "He's so in tune with his mechanics and his arm and how he feels, it's at the point where it's not like we'd leave him out there for 110 pitches. He's feeling as good as he ever does. That's the kicker to it -- how good he feels."

Wouldn't Dempster need at least a simulated game to face hitters?

"I've faced them before," he deadpanned. "I'm hoping they haven't changed too much in the last couple weeks."

No shakes: Bosio keeping it simple with Marmol

ATLANTA -- Carlos Marmol will be the Cubs' closer as long as he throws the pitches that the catcher calls. And if he doesn't, he owes pitching coach Chris Bosio a case of wine.

"I told him, 'You're not allowed to shake anybody off again,'" Bosio said Wednesday.

It's not just one pitch per batter. Marmol cannot say no to his catcher for his entire outing. Bosio implemented the plan when the right-hander returned from the disabled list May 28. How's it going so far?

"I already lost," Marmol said, laughing.

He had to pay up for a couple of shakes in one game, but since then, Marmol is 6-for-6 in save opportunities.

"I do what the catcher says now," he said. "I think it helps a little bit. When I called the pitch, I was thinking too much. When the catcher calls the pitch, it's, 'OK, let's go.' It's a good idea. It's a smart idea from him."

Marmol was 2-for-4 through May 2 in save situations, and Cubs manager Dale Sveum decided to switch to someone else after too many walks. Then, Marmol was sidelined with a hamstring injury. Now, he's got his job back.

"We're trying to simplify things, and it's working," Bosio said. "Sometimes it's more than a grip or a sign or a sequence. I think it's helped his overall mental approach."

Reminded that he's 6-for-6 since doing it Bosio's way, Marmol smiled.

"I better listen," Marmol said. "It works now, and we're going to keep it the same way."

Extra bases

• Luis Valbuena is hitting when it counts.

Valbuena, who has taken over the third-base job for the Cubs, was batting .357 with runners in scoring position and .205 when nobody is on base.

"I'm aggressive every time," Valbuena said.

"If you're going to be any kind of hitter, that's the kind of hitter you want to be," Cubs manager Dale Sveum said. "It's not how many you get, it's when you get them. Some guys are like that. There's not enough of a track record to say that's the kind of hitter he is, but it's been nice for us that when he's gotten his hits, it's been home runs or RBIs."

• Manuel Corpas, Rafael Dolis and Jairo Asencio combined to walk seven batters on Tuesday.

"It's very discouraging," Sveum said, also bothered by starter Chris Volstad walking three in 4 1/3 innings for a total of nine free passes in the game by Cubs pitchers. "To think you can go out there in a Major League game and walk nine guys, it's not acceptable at all. They weren't competitive walks either. They were four-pitch and five-pitch walks. Those guys have to figure it out. We can't keep using them in those kind of games. They're going to have to pitch in closer games, and you have to throw strikes -- it's the bottom line."

• Third baseman Ian Stewart will have surgery on his left wrist on Tuesday at the Cleveland Clinic. Stewart, likely done for the season, has been bothered by soreness all year.

• Cubs television analyst Bob Brenly is taking a mini vacation, missing the rest of the team's games before the All-Star break to watch his son, Michael, who is playing for the Cubs' Double-A Tennessee team.