Maddon has had instances where his team has acquired a player, and it wasn't an upgrade.
"You want to bring somebody in who's physically talented and fits what you're looking for, and beyond that, fits, period," he said.
The Cubs hope to get Fowler back this weekend for their series against the Brewers. Both he and Soler were to begin rehab assignments on Tuesday night with Triple-A Iowa, but the game was postponed because of rain. Iowa will play a doubleheader on Wednesday.
"We have a lot of guys from within," Maddon said. "I can't tell you if there's anybody coming from outside. I know [the front office] is speaking to a lot of different groups. We have guys here who we have to look at."
Nathan is one of those in-house options. The 41-year-old right-hander, who is coming back from Tommy John surgery, has been rehabbing at Double-A Tennessee and Iowa, and he has given up two earned runs over nine innings combined while striking out nine.
Fowler has been on the disabled list since June 19 with a right hamstring strain, while Soler has been sidelined since June 7 with a left hamstring strain. Cahill went on the DL July 9 with right patellar tendinitis.
• Outfielder Kyle Schwarber, on the 60-day disabled list after tearing two ligaments in his left knee in the third game of the season, will see the doctor who did the surgery and get a progress report. If all goes well, Schwarber could start jogging. He is not expected back this year.
Carrie Muskat has covered the Cubs since 1987, and for MLB.com since 2001. She writes a blog, Muskat Ramblings. You can follow her on Twitter @CarrieMuskat and listen to her podcast. This story was not subject to the approval of Major League Baseball or its clubs.