The 24-year old lefthander whose pitches have been clocked at 105 mph has a 6-3 record with a 3.27 ERA in 69 relief appearances over the last two seasons with Cincinnati.
But the small-market Reds want to see if they can maximize their uncharacteristic $30 million investment.
"We are going to stretch him out," manager Dusty Baker said. "We are going to see if there is enough time and he can do it. If there isn't enough time or quality, we can send him back to the bullpen."
Chapman was supposed to pitch in the Arizona Fall League as a starter, and then in one of the Puerto Rican winter leagues. But shoulder soreness canceled the plan.
"We would have the answers by now," Baker said, "if things went according to plan."
Now, it's up to the spring training results.
"I worked hard all winter to get myself mentally and physically prepared to be a starter," Chapman said through an interpreter. "I have been here for 2½ weeks to be prepared."
Along the way, Chapman's shoulder received the rest it needed.
"I feel," he said, "that I'm in good shape."
If he is unable to prove himself as a starter, Baker and the Reds have a backup plan.
"A lot depends on how he does, but it also depends on our needs," the manager said. "If he doesn't make the rotation, we could send him to (Triple-A) Louisville. But I wouldn't be opposed to having three lefthanders in our bullpen."
Chapman had 71 strikeouts last season, and has 90 for his career.
"If they make the decision to put me in the bullpen," he said, "I will continue to work hard to prove that I can be a starter and work all the innings they want me to."
Chapman is the lone lefthanded candidate for the starting rotation, but that is no guarantee that it will sway his manager.
"You prefer a lefty in your rotation, but you want to go with your five best starters," Baker said. "A good righty is better than a bad lefty."
Still, the Reds -- as well as Chapman -- are hoping for a successful transformation.
The Reds, a year after making the postseason, went a disappointing 79-83 last season, finishing in third place of the National League Central division.