CHICAGO -- Cubs manager Dale Sveum called Bryan LaHair Monday morning to give him a heads up. LaHair was going to start in right field for the first time this season, which means first baseman Anthony Rizzo's arrival may be soon.

Rizzo was batting .364 and leading the Pacific Coast League with 23 home runs at Triple-A Iowa, hitting a two-run shot in the seventh inning on Sunday. The Cubs have said they don't want to rush Rizzo and they are sticking to a plan, but Sveum keeps checking his e-mail to get daily updates on the young first baseman.

"Obviously, LaHair playing right field is something that might eventually happen," Sveum said. "There's a day when Rizzo is going to be here, so this is getting him acclimated to the outfield, too."

When? Neither Sveum nor Cubs president Theo Epstein will say. Last year, Rizzo was batting .365 with 16 home runs at Triple-A Tucson when he was promoted to the Padres, and he struggled, batting .143. He's made some adjustments this year, which include lowering his hands, and has wowed everyone who sees him.

"I got to see Rizzo hit like four [homers]," said Cubs catcher Geovany Soto, back from a rehab assignment at Iowa. "He was destroying it down there. He's got some pop. He's doing it right there. He's coming along pretty good. He slid into the wall one day, and he's playing aggressive. It's good to see."

Epstein wants to make sure the timing is right.

"You have to look at what happened last year," Epstein said Monday. "He had great numbers and was rushed a little bit and came up and struggled, so it's important to put players in position to succeed, and always put your Major League club in position to succeed. You see with the lineup tonight we might be taking a look at players in different positions to allow the team to be in a position to succeed when we do potentially make a move. Those things you don't want to rush into, there's more to development than numbers."

LaHair has only played first this year and played outfield last season. He didn't think it would be a major adjustment to switch, saying the work he did in Spring Training will pay off.

"I think in the back of my mind there was always the thought of me moving to the outfield at some point," LaHair said. "It was more of a surprise last year when the only thing I played was the outfield. This will be a new challenge and I'll be working defensively in a different spot. It's all fun."

Sveum and the Cubs could use some pop. The team was batting .246 and ranked 13th in the National League in slugging percentage at .380. Sveum has checked the video to monitor Rizzo's progress this season. Has he seen improvement?

"He's been pretty good the whole year," Sveum said. "He's one you go to the computer every day to see what he did and I think yesterday he hit one of the longest home runs in Iowa history. He's having one of those years and he had it last year, too, in Triple-A. I think lowering his hands had a lot to do with it and confidence."

Right now, Rizzo is staying in Iowa.

"We had a plan to start with, so there's no early arrival or anything like that" Epstein said. "We knew he had to develop and we had a game plan and we were going to stick to it."

Soto activated from DL, Castillo optioned to Iowa

CHICAGO -- Cubs catcher Geovany Soto was activated from the 15-day disabled list on Monday and Welington Castillo optioned to Triple-A Iowa.

Soto had been sidelined since mid-May after undergoing arthroscopic surgery to repair a torn meniscus in his right knee.

"I had a good week [at Iowa] and was in plenty of games," said Soto, who was 3-for-16 (.188) in five games with two doubles.

Soto was batting .161 when he was sidelined with the knee injury, which he felt May 16.

"I had a lot of at-bats [in Iowa] and tried to find myself and I think we're on the right track," Soto said.

The Cubs had talked about keeping three catchers, but decided Castillo needs regular at-bats to develop. Steve Clevenger is the backup catcher, although he started at first base on Monday.

Soto has been eager to return.

"After the surgery, all I wanted to do was come back ready as fast as I could," Soto said. "It was a little frustrating -- being on the DL is no fun."

Extra bases

• This series is the second meeting between the Cubs and White Sox, and even though it's manager Dale Sveum's first exposure to the intracity Interleague rivalry, he's prepared.

"You've been in these things before so you know what to expect," Sveum said Monday. "They're different than any other games in the season. The rivalry, whatever it might be, it's a unique series. There's more to it than what people think. A lot of times you don't realize they are different games. The atmosphere is different, everything about it is different."

• Alfonso Soriano will be the designated hitter for all three games against the White Sox. He already has hit three home runs this season as the DH, which is tied with Glenallen Hill for the most by a Cubs designated hitter. Soriano also has eight RBIs as the DH, which is tied for the most by a Cubs player with Hill and Derrek Lee.

• Sveum was asked by a television reporter the biggest thing he's learned about himself in his first year as manager.

"About myself? Not too much," Sveum said. "I knew myself pretty well going into this. I haven't learned a lot about myself."