GOODYEAR, Ariz. -- There are several young Reds pitchers coming off their rookie seasons who are vying for jobs in the rotation and bullpen. Right-hander Luis Castillo, 25, doesn't have that pressure or worry despite a resume of just 15 big league starts.
It's what Castillo did during those starts that has him already locked into Cincinnati's rotation and an ace in the making.
"There's a lot to like about this kid," Reds manager Bryan Price said. "That's why I'm confident in saying, barring any complete and total failures either physically or performance-based, I don't see a situation where he wouldn't make our rotation."
Acquired in the previous offseason from the Marlins in exchange for pitcher Dan Straily, Castillo made the jump from Double-A Pensacola to the big leagues for the Reds on June 23. In his 15 starts, he was 3-7 with a 3.12 ERA and a 1.075 WHIP.
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Over his 89 1/3 innings, Castillo walked 32 while striking out 98.
"I feel really happy for this year. This was my goal, I wanted start with the team," Castillo said via translator Julio Morillo. "Confidence is the key. I feel confident that I can do my job. I compete knowing I'm going to get outs."
Castillo came to the big leagues with three proficient pitches -- a four-seam fastball that averaged 97.5 mph, according to Statcast™, and could easily reach 100 mph. He had a changeup that held hitters to a .138 average. It produced 78 whiffs out of 335 times thrown. Castillo also developed a slider last spring and perfected it at Pensacola with pitching coach Danny Darwin.
"It's a special collection of talents that allow him to compete against the best in the league and did a lot more than simply hold his own," Price said. "I thought he was better than the league for a good portion of the time he was on the mound for us."

A month into his big league career, Castillo added a fourth pitch with a two-seam fastball/sinker. It came at the suggestion of pitching coach Mack Jenkins, but its debut came in improvisational fashion July 25 vs. the Yankees in New York.
"I remember I started throwing it on the side before the game at Yankee Stadium," Castillo said.
In the second inning with the bases loaded and no outs, Todd Frazier came to the plate. Castillo used a two-seamer against him.
"I said 'OK, this has to be the pitch that I have to throw right now to get a ground ball. So I threw it," Castillo said. And everything works out."
Frazier grounded to short and the Reds turned a triple play.

"After that, I knew that pitch was good enough for the rest of the season," Castillo said.
In the following start vs. the Marlins, Castillo was throwing 98-mph two-seam fastballs in the eighth inning and struck out Miguel Rojas with one. The pitch, which averaged 97 mph his final nine games of the season, had the opposition batting .230.
Reds reliever Jared Hughes, who specializes in throwing the sinker, has been throwing the pitch since he was a kid playing catch with his father. Castillo added the pitch on the fly and had immediate success.
That doesn't usually just happen.
"I think that speaks to how confident he is," Hughes said. "It speaks to his feel for pitching. Not everybody can do that. If I try a different pitch, it will take me two months and I still can't get it. Castillo is gifted. He's got a great feel for pitching. His ability to turn on the two-seamer like that is just a sign of things to come."