Contreras, 24, ranked No. 2 among the Cubs' top 30 prospects on MLB.com's list, made a splash Sunday night in his first big league at-bat, delivering a pinch-hit home run on the first pitch he saw. He started at catcher Monday with veteran John Lackey and was paired with Jason Hammel on Tuesday.
"He's looking really good right now," Maddon said. "You don't want to put too much on his plate right now."
The Cubs are hoping veterans Miguel Montero and David Ross tutor Contreras, even if it means less playing time for them, especially Montero.
"[Montero] has been very accepting and very helpful to Willson," Maddon said. "On the bench [Monday] night, he was in the kid's corner verbally the entire evening. He understands what's going on. He's still going to play and play a lot. Willson, coming off what he did in the Minor Leagues, he's been playing well and hitting well, and it's important to keep that going."
Contreras batted .350 at Triple-A Iowa before he was called up.
"Just let him play, let him be Willson, let him be 24 years old, let him be a new player in the big leagues and let him grow into this whole thing," Maddon said. "He's going to be really good. I like the potential for him to break in this way with two outstanding veteran catchers around him."
Fowler hoping to play in All-Star Game
Cubs team doctors told Dexter Fowler he would likely be sidelined one week with his strained right hamstring, and he knew he'd need to get some at-bats, so he agreed to go on the disabled list rather than have the team be short-handed.
"It's not later on in the season, and it wasn't as bad as it could've been," Fowler said of the timing and the injury. "Hopefully, when it's time to come off [the disabled list], I can come off."
He felt soreness in his hamstring on Saturday as he ran to first.
"I didn't feel it when I was taking off, but in the middle of the run, I felt it," Fowler said. "I took some more steps, but I knew it wasn't right."
Last week, Fowler was leading National League outfielders on the 2016 Esurance MLB All-Star Game Ballot, and he was hoping he could go to the game.
"I tell my wife all the time; I didn't know that many people knew who I was," Fowler said, laughing. "It's definitely awesome [to get the support], and I hope I can still play if I make it."
• Reliever Carl Edwards Jr. said he kept an eye on how the Cubs were doing but spent most of the time preparing for another callup. Last year, he was promoted on Sept. 7 and appeared in five games in relief.
"I was real nervous the first time coming up," Edwards said. "I actually feel like now, I can stay here."
• Cubs pitcher Jake Arrieta will be included in ESPN The Magazine's annual Body Issue. The promotional video shows a naked Arrieta pitching. Maddon was asked if he'd ever consider posing for the magazine.
"If I'd been asked 30 years ago, 40 years ago," Maddon said.