CHICAGO -- The Chicago Cubs have begun discussions on September call-ups but are being careful they don't change the chemistry in the clubhouse.

"The last thing you want is too many guys down there and it kind of disrupts the vibe of what's been going well," general manager Jed Hoyer said Tuesday afternoon. "You have a lot of factors at play."

One factor is the actual size of the clubhouse. Next year it will be one of the largest in baseball, but until renovations are done it's one of the smallest. That's not to say the Cubs are going to keep a needed player from getting called up.

Hoyer said arms to cover blowouts and rain delays are obvious priorities plus some bench depth. Philadelphia Phillies second baseman Chase Utley doesn't sound like a possibility anymore as general manager Ruben Amaro told a radio station he's likely to stay with Philadelphia through the end of the season. It means injured infielder Tommy La Stella could finally play a September role for the club.

"I think he's a big league hitter," Hoyer said. "Giving him at-bats makes sense."

The Cubs are letting La Stella play every day at Triple-A Iowa as he's missed all but two games this season with an oblique injury. Javier Baez is also an obvious choice to be called up. He's missed time with a passing of a family member as well as a wrist injury.

"Our depth is improving," Hoyer said. "We may call up some guys on the first and we may call up some guys when Iowa is done."

One arm they might call on is righty Carl (CJ) Edwards. Acquired in the deal that sent Matt Garza to Texas in 2013 he's an intriguing option. He's 5-3 this season with a 2.87 ERA split between Double and Triple-A. The Cubs are monitoring a callus Edwards developed on one of his pitching fingers on Monday night.

"He's had a nice year," Hoyer said. "I think he's gotten better and better."

You can expect some of the usual names like Zac Rosscup, Brian Schlitter and Yoervis Medina to return as well.

"You can't have too many arms in September," Hoyer said.

Hoyer also indicated Neil Ramirez isn't expected back anytime soon as he's had an injury plagued season with shoulder and side problems. Meanwhile, ailing righty Rafael Soriano threw a simulated game on Tuesday and will head out on rehab assignment soon. Soriano's shoulder has been sore.

"Our hope is once he gets right he can help us," Hoyer said.

It's the first time in years the Cubs are calling players up to help them in a pennant race and not just to get experience. There's still a chance they could go outside the organization for help through a waiver deal but no matter what they do keeping the right mix in the clubhouse will be of utmost importance.

"We've started those meetings and we'll keep having them up until the first," Hoyer said. "You also want to make sure you don't ruin your clubhouse in September."