CHICAGO -- The Cubs' top prospect, Anthony Rizzo, was removed for a pinch-hiter in the sixth inning of Sunday's game with Triple-A Iowa because of right wrist soreness and the Cubs are expected to get an update on Monday, Cubs president of baseball operations Theo Epstein said.

Epstein said Rizzo felt soreness in the wrist after he swung and missed, but an X-ray taken Sunday came back clean.

After Rizzo was lifted for a pinch-hitter, speculation began that the hot-hitting 22-year-old first baseman -- who has a .354/.415/.713 slash line with 17 home runs and 46 RBIs in 48 games -- could be getting called up to the Majors.

The Iowa Cubs' official Twitter tweeted: "We have no further information on Rizzo. FWIW [For what it's worth]: All transactions involving Iowa Cubs players are always announced first in Chicago."

The affiliate's tweet turned out to be premature.

"It happens, I understand it," Epstein said. "It's part of the modern world. Things happen that didn't happen 10 years ago because of technology, and we all have to adjust."

Epstein and general manager Jed Hoyer reiterated Monday their plans to let Rizzo continue to develop in the Minor Leagues.

With the Cubs mired in a 12-game losing streak and 14th in the National League in runs entering Monday, fans have been hoping to see Rizzo's bat in the Major League lineup. Hoyer said he wouldn't put that kind of pressure on Rizzo.

Instead, Hoyer said it's up to the current Cubs to help snap the team's 12-game losing streak.

"No young player should ever be viewed as the savior or the changer of a struggling Major League offense," Hoyer said. "We have a lot of veterans on this team. We're going to get through this and get on the right track because of those veteran guys, not because of those young guys coming up through the Minor Leagues."

Cubs frustrated by skid, but won't panic

CHICAGO -- Frustrated.

That's the best way to describe how everyone involved with the Cubs' 12-game losing streak entering Monday feels. The players, coaches, president of baseball operations Theo Epstein and general manager Jed Hoyer.

"I'm really frustrated, along with everybody else," Epstein said Monday afternoon at Wrigley Field before the Cubs played the Padres.

"It's frustrating," Hoyer said. "You never want to go through this, and when you do, you don't get a lot of sleep."

The Cubs entered Monday's series opener against the Padres with 12 straight losses, their longest drought since opening the 1997 season 0-14. It also is the seventh losing streak of 12 or more games and the 15th double-digit losing streak in franchise history.

Although Epstein and Hoyer said they were frustrated with the losing streak, both stressed they are committed to building long-term success.

"It's important for us to stay disciplined and for us to take a step back, too, and realize that what we're trying to accomplish here requires some time and some changes and some growth as an organization," Epstein said. "And to make sure that, even as we're scuffling badly during this period, that we don't lose sight of where we're trying to get."

Epstein admitted he envisioned tough stretches coming this season, his first in Chicago, but said he didn't foresee anything quite like this. The Cubs played well earlier this month, Epstein noted -- they won a series against the Braves and split a two-game set with St. Louis -- and said he doesn't feel the Cubs are this bad.

"I don't think this is indicative of the type of team we are. I think we're clearly better than this and we'll get back to that level," Epstein said. "When you're not the most talented team on the field on a regular basis, you have to play well to compete. And if you don't play well, you run the risk of stretches like this."

As for tinkering the roster, Hoyer said the club regularly has conversations about what they can do to shake things up, but added late May is not a big trading time. Because of that, most of the Cubs' options come from within. Hoyer said the Cubs "don't have the most flexible roster in the world," and said he wouldn't drop players just to drop them.

One internal option fans have been clamoring for is first baseman Anthony Rizzo, who is hitting .354 with 17 home runs in 48 games at Triple-A Iowa. Epstein and Hoyer said they don't want to rush Rizzo, repeating that the 22-year-old's development is most important.

"We're not bringing him up here as a changer of our fortunes," Hoyer said. "That's not fair to him."

For now, Hoyer said the Cubs will lean on veterans to help lead them out of their current funk that, he and Epstein hope, is part of the maturation process for an organization they're trying to rebuild.

"This is a real painful bump that we're going through right now to get there. My hope is, certainly, in years further, we're looking back at this as a character-building thing," Hoyer said. "Right now, it doesn't feel like character building at all. It feels like a 12-game losing streak, and we need to get through it."

Cubs activate Marmol from DL, option Dolis

CHICAGO -- Cubs right-hander Carlos Marmol was activated from the 15-day disabled list Monday and was available for the team's series opener against the Padres at Wrigley Field.

Right-hander Rafael Dolis was optioned to Triple-A Iowa.

Marmol, who was placed on the DL on May 12 with a right hamstring strain, made two rehab appearances for Iowa. He allowed one hit in two innings and, on Sunday, struck out the side while walking one and throwing two wild pitches.

"I feel very good, very comfortable -- that's more important," said Marmol, who is 0-1 with a 6.35 ERA in 15 relief appearances for the Cubs this season.

Marmol, who has 16 walks in 11 1/3 innings, said he worked on his fastball and slider and feels comfortable with both. Manager Dale Sveum said Marmol would pitch in the seventh inning and as matchups suggest, the same role he was in prior to his injury.

Now it's Dolis' turn to figure out things in Triple-A. Dolis was 0-2 with a 24.00 ERA in his last five outings.

"It's not a demotion as much as just going down there and getting right and getting back here, hopefully, pretty soon," Sveum said. "He's got to be able to throw strikes. It's hard for me to use him right now because he's lost complete command of his fastball. Go down, hopefully gain some confidence real quick, and he won't be down too long."

Soto says he's close to returning from injury

CHICAGO -- Geovany Soto was in good spirits in the Cubs' clubhouse on Monday as he continues to recover from knee surgery.

The Cubs catcher underwent surgery to repair the meniscus in his left knee on May 18 and said he's close to returning.

"Time-table wise, I don't want to say, but I'm really close," Soto said. "It's going to be like a two- or three-week injury instead of a two-month thing."

Soto said he couldn't pinpoint when the injury took place, but said he felt it during the May 16 game against the Phillies when he dropped down to block balls. He was scratched from the lineup the following day and had surgery the next.

Soto was off to a slow start, hitting only .161, but said the injury didn't affect his performance.

At the time of his injury, Soto joined backup catcher Steve Clevenger (rib cage) on the disabled list. Last week, Welington Castillo was the latest catcher to get sidelined after he sprained the MCL in his right knee.

"Yeah, when it rains it pours sometimes," Soto said. "It's a tough position. It's part of our jobs, but it's a tough job to do."