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06/30/12 4:01 PM ET

Volstad to get start in place of injured Dempster

CHICAGO -- Cubs pitcher Ryan Dempster, on the disabled list with a sore right lat, will throw off the mound Monday in Atlanta, and Chris Volstad will take his spot in the rotation Tuesday against the Braves.

Volstad was sent to Triple-A Iowa after opening the season 0-6 with a 7.46 ERA in eight starts with the Cubs. In eight starts at Iowa, Volstad was 2-3 with a 4.44 ERA, giving up 25 earned runs on 59 hits and 12 walks while striking out 41 over 50 2/3 innings.

"His last outing and even the outing before were pretty positive," Cubs manager Dale Sveum said of Volstad. "It's logical -- it's his day [to pitch] and he's done a good job his last couple outings. It's a logical thing to do."

Dempster, on the DL since June 16, threw on flat ground Saturday.

Cubs impressed by Rizzo's defense at first

CHICAGO -- Anthony Rizzo has looked good at first base in three games with the Cubs. Maybe that's not strong enough.

"He's really good," Cubs manager Dale Sveum said Saturday. "He's the prototypical left-handed first baseman. He's good and it looks a lot better when left-handers are fielding at first base. It's funny how that works."

Cubs general manager Jed Hoyer also was happy with some changes Rizzo has made at the plate since one year ago when the first baseman was in the Padres organization with Hoyer.

"The challenge for him is he's going to go through some adjustment periods and how he gets through those [will be the difference]," Hoyer said. "I think we have to let him play. He's very talented.

"He clearly has nothing left to prove in the Minor Leagues," Hoyer said. "The daily watch of how he's doing is not a great thing for anybody -- just let him play, and look up and hopefully the numbers will be there at the end of the year."

Stewart may require surgery on injured left wrist

CHICAGO -- Cubs third baseman Ian Stewart may need to have surgery on his left wrist, which is not responding to cortisone shots or treatment.

Stewart has been on the disabled list since June 13, and sought a second opinion from a specialist June 18 at the Cleveland Clinic.

Asked if the third baseman would need surgery, Cubs general manager Jed Hoyer said Saturday: "It's a strong likelihood."

Stewart was batting .201 with five home runs and 17 RBIs in 55 games with the Cubs.

"They haven't made a complete decision," Cubs manager Dale Sveum said about the possibility of surgery. "There's some calcification on the bone that's causing some of the problem."

A decision was expected around the All-Star break.

"We're probably going to have to make that decision pretty soon," Sveum said. "There's no progress going on, so we'll have to make that decision."

Said Hoyer: "It's been frustrating for Ian and frustrating for us."

Extra bases

• Cubs general manager Jed Hoyer said the team was in discussions with representatives for first-round pick Albert Almora but added there was "nothing to report."

Almora, 18, selected sixth overall in the First-Year Player Draft, starred at Mater Academy Charter in Hialeah Gardens, Fla.

The deadline to sign is July 13, which has been moved up one month from previous years.

"At least now, no matter what, if you sign at that deadline, you'll get a fair amount of games in before the end of the year," Hoyer said. "We're optimistic and we've had dialogue but beyond that, we're not going to characterize the discussions."

• With the July 31 Trade Deadine approaching, Hoyer said not much has changed as far as interest.

"It's been the same for the last week or two," Hoyer said. "It's our job to be in touch with every team and talking to everyone and making sure we know what's going on, and a lot of teams are checking in with us as well. I think it'll maintain this until a week out and then it heats up before the deadline."

The extra Wild Card team will certainly change things.

"It doesn't take much of a hot streak to get in the race now," Hoyer said. "In the past, if you had two really good teams in the division, the Wild Card wasn't an option. Now, one hot streak and a couple injuries to a team that's leading and everyone feels they're back in the race. It's hard to characterize how it will play out this year. In theory, there should be fewer sellers and more teams looking to add."

Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter@CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.