GOODYEAR, Ariz. -- Dusty Baker would like to have two Aroldis Chapmans -- one for his bullpen and one for his starting rotation.

But the Reds' manager is happy enough that he has one, and on Monday Baker announced that the flame-throwing lefty will start the season in the bullpen. That means right-hander Homer Bailey will begin the season in the starting rotation, and he'll pitch against the Cardinals on April 9.

"That was a very tough decision -- very, very tough because Chapman could either be one of our best starters or our best relievers," Baker said. "It's a situation where with the injuries that we have, and starting out early in the season where the starters are lucky to go five or six innings, we need to shore up our bullpen."

Bailey's inclusion fills out the starting rotation. Johnny Cueto will pitch the club's season opener against Miami, followed by Mat Latos, Bronson Arroyo, Bailey and Mike Leake.

Baker said the struggles of lefty Bill Bray partially led to his decision to put Chapman in the bullpen. Baker said Bray "isn't a candidate right now to be a late-inning lefty guy," meaning Baker is planning to use Chapman in a very prominent relief role deep in games.

In the spring, Chapman looked very good in what many thought was his audition for a starting role. He went 2-0 with a 2.12 ERA in five appearances -- four of them starts. But he has yet to start a regular-season game, going 6-3 with a 3.27 ERA in his 69 appearances over two seasons with the Reds.

Baker reiterated that nothing is set in stone with his pitching staff -- or the rest of the roster. That's especially true now with his decision to start the season with 14 position players and 11 pitchers because of an early off-day.

The team will re-evaluate and possibly adjust the roster this weekend, depending on how well the pitching staff is preserved through the season's first couple of games.

"That's the story of this whole year," Baker said. "Until we get everything back together, it could be one of those dot-dot-dots -- to be continued."

As for Bailey, who gets the start after he went 9-7 with a 4.43 ERA last season, the thought of facing the Cardinals in the two teams' first meeting of the season is a prospect that has him excited.

"I haven't really thought about it like that, but I guess it sounds pretty cool," Bailey said of facing the defending champs. "It's just the first game of the season, though. It's a team that we know the hitters quite a bit so that brings some comfort."

This spring, Bailey is 1-2 with a 7.98 ERA in five starts, though he's confident enough with the finish to his Cactus League season to carry some positives into the regular season.

"Spring's kind of always the same," Bailey said. "For a pitcher, you're working on your fastball location and start working your way through and build your innings. My last game through, I finished. I threw well, and it's back into baseball mode."