Rondon was 18-for-22 in save situations and had a 1.95 ERA entering Wednesday.
Maddon wasn't sure if he'd get Chapman into Wednesday's game. The lefty joined the Cubs on Tuesday and last pitched on Saturday for the Yankees. He was 20-for-21 in save opportunities with a 2.01 ERA in New York.
• Jason Heyward was on the field Wednesday, doing drills with hitting coach John Mallee, which has become part of his regular pregame routine. The Cubs are hoping Heyward sticks with it, because it's been a tough first season in Chicago.
Entering Wednesday, Heyward was batting .108 since the All-Star break, and overall, had a .315 slugging percentage, last in the Majors among 159 qualified players.
"He's probably struggling a little bit," Maddon said. "It's not easy to go through what he's going through right now. ... We're just trying to get the ball in the air more consistently."
Heyward has hit the ball hard, but right at defenders quite a bit. His batting average on balls in play is .273.
"He'll come out on the other side because he's good and he's working at it, and I like the plan of attack that he and John have going," Maddon said. "You don't always get overnight results. I know people will get less patient than I will or he will. The biggest thing is that Jason doesn't get impatient. You never want him to be the guy to give up on what he's doing. I have a lot of faith in him. I think he's hit some balls really well without any luck lately."
• Clayton Richard was designated for assignment to make room on the roster for Chapman. Richard was 0-1 with one save and a 6.43 ERA in 25 appearances for the Cubs.
"He's just a solid human being and professional," Maddon said. "We'd love to have him back. He never arrived at that level that we saw him at last 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.