Castro suffered the injury on Feb. 27 while running out a ground ball, and the Cubs have taken extra precautions with their young star.
"They want to be careful," Castro said. "I don't want to go in now and maybe miss one month of the season. We are going to make sure everything is good so I can play the whole season."
Castro played the entire 162-game schedule in 2012 and wants to do the same this season.
"That is an important goal for me," he said. "I don't care where or in what league, I like to play."
Castro reported to camp 10 pounds heavier this spring than he weighed in 2012, and the club has encouraged him to drop some weight during his rehabilitation.
Castro has been taking ground balls and some batting practice while the team's trainers help bring him back to health.
"They had me running (40 yards) the last couple of days and it feels fine," he said. "I feel good and I don't have any pain right now."
Part of Castro's rehab consists of core exercises to increase the strength in his stomach, hamstrings and quadriceps.