As of early afternoon, Castro was just one of three Cubs who have not reported. Alfonso Soriano and infielder Junior Lake are the others. A source familiar with the situation said Castro will arrive in Mesa on Thursday and work out on Friday, which is what's required by the team.
The Chicago Police Department investigation into a sexual assault complaint against Castro, based on a Sept. 28 incident, is ongoing, a CPD spokesman said Thursday.
Castro's representatives have denied the allegations.
"Everything is what it is right now," said Sveum, who's in his first year as Cubs manager. "Spring training is upon him, which I'm sure he's looking forward to.
"So you just tell him to be himself and don't worry about the other distractions. It's baseball season now and that's all you have to worry about."
The Cubs' first full workout for position players is Friday. All position players have five-minute one-on-one meetings scheduled with Sveum before the workout.
Doug Padilla covers the Cubs for ESPNChicago.com and ESPN 1000. ESPN Chicago's Bruce Levine contributed to this report.