News broke Thursday that the Cubs and Castro's agent, Paul Kinzer, have been working on a contract extension that could be as long as six years and take Castro beyond his initial free-agent years.
While some players might not be so revealing in the hopes they don't hurt their negotiating leverage, Castro had no such worries.
"It's very important for me," Castro said of a potential long-term deal. "My (feeling) is that I want to be here and I want to be with the team for a long time."
The main knock early in the career of the wildly talented Castro is that he can lose focus at times. This season alone, he has forgotten the number of outs while on defense and has been thrown out on the bases while losing track of the ball when attempting a risky base-running maneuver.
Midseason contract negotiations would seem to have the potential for more distraction, but Castro is doing his best to make sure it isn't an issue.
"I'm letting my agent work," Castro said. "I tell him, 'You tell me when you're close. When you're close and ready to do it, you tell me.' But right now, I give more concentration to the game."
Castro continues to regret his base-running miscue during the previous homestand in a game against the Cincinnati Reds. Manager Dale Sveum was perturbed afterward and said he considered putting Castro on the bench for a game but never went that far with his discipline.
Despite being just 22, Castro refuses to make excuses for his miscues.
"One part about that, I am young but it doesn't matter, I play baseball," Castro said. "You play baseball in the minor leagues a lot too. I want to be on this team my whole career. I don't want to go anywhere. I want to finish my career. That's why I tell my agent that I want to be here. If they want me to be here I will be there. I'm working hard to help the team win."
Despite playing for a team that hasn't had much success since he arrived in the big leagues (the Cubs are 179-232 since he played his first game), Castro has found plenty to like.
"(Chicago) is one of the best cities I ever see," he said. "Good team, everybody is together. Good people, boss people like (president) Theo Epstein and (general manager) Jed Hoyer. Those are the guys you want to be with your team to make them good for the future. That's what I want to be. This team will be good to win games and be in the playoffs and I want to be there."