"I like the way he's been going about his business for the first three days in camp defensively," Sveum said Tuesday. "It's one thing I challenged him to do. [I said] 'Your next step now is to win a Gold Glove,' and obviously that takes a lot of focus and hard work and being focused for 150 pitches a game and 162 games. He's got the ability to do it. The rest is up to him."
He's got some work to do. Castro committed 27 errors last season, the most among National League shortstops. He had the 10th-best fielding percentage (.964) among NL shortstops. The Phillies' Jimmy Rollins made 13 miscues in 152 games and compiled a .978 fielding percentage.
"I know that God gave me [the ability to] hit," Castro said. "That's why when I went to the Dominican, I worked hard every day on my defense. I want to be like Barney and win a Gold Glove. It's going to be fun to win a Gold Glove at shortstop, second base and first base. It's going to be fun because Rizzo is very good, too.
"It's good motivation for me," he said. "I know I can be like those guys and play good defense."
The problem in the past hasn't been lack of effort, but lapses in concentration. Castro is aware of the need to stay focused.
"My game plan is going to be perfect," he said.
The Cubs feel Castro can do it, and last August, rewarded him with a seven-year, $60 million contract.
"It didn't change anything," Castro said of his new deal, "but you feel a little more relaxed because my family is going to be good now. I can just play baseball and forget about everything."
The Cubs project more power after Castro hit a career-high 14 home runs last season. Wrigley Field's wind robbed him of a few more.
"I think the next step for him more than that is to become more of a winning type of hitter," Sveum said.
That involves more than just hitting with runners on base.
"It's just understanding any situation about driving runs in," Sveum said. "It's having great at-bats in key situations and not trying to do too much when the game is on the line and things like that. It's knowing and grinding out at-bats and not making quick early outs on pitchers' pitches."
Sveum knew about Castro's mental glitches -- he'd heard about the nationally televised game when the shortstop was caught on camera looking away while James Russell threw a pitch -- but didn't see that last season.
"Hopefully, he just keeps improving and that's all we're asking for from a guy like him," Sveum said.
"The only thing I want is to help my team to win," Castro said. "I see myself my whole career [being] at shortstop -- and [being] a good shortstop, not a shortstop just because I'm a shortstop. I'll be a shortstop who can win, [earn a] Gold Glove, can hit, everything."
The Cubs do have a future shortstop in camp this spring in Javier Baez, the team's No. 1 Draft pick in 2011 and ranked by MLB.com as the club's top prospect, but he played at Class A last season. Castro is a two-time All-Star.
"He's pretty good, real good," Castro said of Baez.
Is Baez better than Castro?
"I don't know," Castro said, "but he's good."
If the Cubs can get good, how much better can Castro be?
"I'd be like more superstar than I am, that I can be, like I'm supposed to be," Castro said. "I know I can be very good because I'm never lazy. I work hard every day."
"He loves to play," Sveum said of Castro, who turns 23 on March 24. "We're a better team when he plays."