"I just have to work hard," Castro said.
The young shortstop, who rocketed through the Cubs' Minor League system last year, going from Class A to the Arizona Fall League, made quite a first impression on manager Lou Piniella.
"The ability is there, there's no question," Piniella said. "He's got good hands, he's got a good throwing arm and from what I saw today, he's got a nice swing. We'll just let him go out there and play and gain some experience."
Castro, who turns 20 on March 24, is expected to open the 2010 season in the Minor Leagues, but he's created quite a sensation. Baseball America ranked him as the organization's top prospect after he hit .302 at Class A Daytona, then .288 at Double-A Tennessee. He was the youngest player in the Arizona Fall League and totally unfazed, batting .376 in 26 games for the Mesa Solar Sox. Someday, he could be the Cubs' first All-Star shortstop since Shawon Dunston.
On his first day in big league camp, Castro was inserted into a hitting group that included superstars Alfonso Soriano, Aramis Ramirez, Kosuke Fukudome and Minor League catcher Welington Castillo. Not bad company.
"He's very young, but mentally, he's older than 19," Soriano said of Castro. "He knows what he wants to do. I think he'll be OK."
"We'll watch him," said Piniella, who will have coaches Alan Trammell and Ivan DeJesus keep an eye on the youngster. "We'll get a good feel for him this spring. These kids will let you know when they're ready. The special ones, they come quick. ... The special players, you don't look at their age, you look at what they do on the field and how they react and if they have a bad day and how they bounce back."
At first glance, Piniella said Castro reminded him of a young Edgar Renteria.
"He's got good hands," Piniella said of Castro. "He can swing the bat. He uses his hands well to hit and he stroked the ball quite well for his first day."
Castro has followed shortstop Hanley Ramirez's career more.
"I never asked anybody to compare me with [Renteria]," Castro said. "I just like to play the game the right way."
Castro is smart enough to know he needs more experience. Piniella's ability to speak Spanish made Castro feel comfortable. The young infielder's English will come. On Tuesday, infielder Andres Blanco acted as interpreter.
Soriano would watch movies like "Rush Hour" and "Rocky" to learn the language. It's difficult for Dominican players to test their English because they don't like being laughed at. Soriano knows what Castro is going through.
"It's his first year and I know how he feels," Soriano said. "My first year, I felt like I didn't know anybody. It's good that we're together [in the hitting group] and he can be more relaxed."
When Soriano came up with the New York Yankees, he had Bernie Williams, Luis Soto and Mariano Rivera take him under their wing.
"Those guys gave me a lot of motivation and talked to me," Soriano said.
What about Castro?
"I think he has very good talent and I think he can be a very good player," Soriano said.
Facing the media was probably the hardest part of Castro's day. Was being in the big league camp overwhelming for the teenager?
"I worked hard for this," Castro said.
Was he nervous?
"No," Castro said.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.