Chapman played long toss before Friday's game at Miami and threw 40 pitches.
"I felt really good," the hard-throwing left-hander said through a translator. "I feel a lot better."
The Reds decided to give him five to seven days off after his velocity and control were subpar Monday against Pittsburgh. He said he doesn't expect to pitch this weekend in Miami.
"A few more days, I'll be back," he said.
Manager Dusty Baker said Chapman is on schedule to return soon.
Chapman, whose fastball often reaches 100 mph, said his shoulder began to feel tired last week. He said he has gone through the same thing two or three times before, most recently last year.
Chapman moved into the closer's role this season for the first time in his career. He has converted 35 of 40 saves with a 1.60 ERA in a career-high 64 appearances, and he made the All-Star team.
With the NL Central-leading Reds closing in on a playoff berth, Chapman said the timing of his break isn't ideal.
"I don't feel good about it," he said. "I wish this would have happened early in the season, because this is when we're in the final stretch."
But the goal, he said, is to be at his best in October.
"By then I hope to be a lot better than I am right now," he said.