"I felt really well today," said Chapman, who threw 89 pitches.
The most important question to come out of the game: was it enough to earn Chapman the fifth spot in the rotation? For now, that is still unanswered.
"I don't know, man," Reds manager Dusty Baker said. "We haven't come up with [the answer] yet. Honestly, we have not decided yet. There are more people involved here than just Chapman."
One of those people is Homer Bailey, who is out of options. The Reds are also short in the bullpen because of injuries to closer Ryan Madson and set-up man Nick Masset. Chapman was a reliever the last two seasons while Bailey has never worked in a bullpen role.
Chapman clearly has had the better camp of the two pitchers. The 24-year-old lefty, who has a 2.12 ERA, has given up only two walks while striking out 18 this spring over five big league games.
"He's had an excellent spring," Baker said. "He's worked hard. He's more engaging. Everything is positive."
On the other hand, Bailey has a 7.98 ERA with seven walks and six strikeouts in his five big league spring starts. He worked six scoreless innings with four hits, one walk and five strikeouts against a Triple-A team on Thursday.
Of all the things that have gone right for Chapman this spring, the one he is most pleased about is his walks-to-strikeouts ratio. According to STATS Inc., Chapman led all Major League relievers last season with 13 first-batter walks and he had 41 walks with 71 strikeouts over his 50 innings in 54 games.
"I feel real happy with the way things went in camp," said Chapman through interpreter Tomas Vera. "Being able to have a less amount of walks, it was my goal when I came to Spring Training -- to work on my command. "
Against Milwaukee, Chapman stuck with a steady diet of mostly fastballs and sliders, and said he wasn't feeling comfortable using his split-fingered fastball.
Following the wild first offering to Weeks, he hit a leadoff double and Nyjer Morgan followed with a single but was caught overrunning first base in a nice defensive play by the Reds. Chapman escaped when Weeks was thrown out in a fielder's choice.
The inning ended when Aramis Ramirez struck out on a 94-mph pitch. It wasn't a fastball, but a slider with that high velocity.
Brewers manager Ron Roenicke said Chapman the starter looked just like Chapman the reliever, with the same hard heat and nasty slider. Opposing starter Randy Wolf counted his sharp groundout in the third inning as a personal success.
"Just making contact off him, it's a moral victory," Wolf said.
A two-out jam came after a pair of Brewers singles in the fourth. Chapman should have escaped with a scoreless inning, but third baseman Juan Francisco struggled with a grounder and a late throw to second base. It looked like an error but was ruled a fielder's choice. Chapman hit Morgan in the back with a fastball and surrendered a Ryan Braun double with one out in the fifth, but no one scored.
Chapman, who has the fastest big league pitch on record at 105 mph, is not believed to have eclipsed the 100-mph mark this spring.
"I don't know if I can throw harder or not," Chapman said. "I'm trying to work on my command, and trying to be ahead of the count. Down the road, maybe the plus speed will come back. I'm not looking for speed right now."
The Reds will break camp following Monday's game and have an exhibition game scheduled for Tuesday against the organization's Minor League prospects in Cincinnati. That would be Chapman's and Bailey's next turn to pitch but the starter has not yet been named.
Chapman wasn't ready to say whether he's earned a rotation spot.
"I don't know," he said. "I think that's not my decision. You have to wait until the end."