This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

CHICAGO — Chicago Police Superintendent Eddie Johnson is recovering after a successful kidney transplant.

At a news conference Thursday, doctors said Johnson is alert and sitting up

“One of the things he asked is ‘when can I get back on the treadmill?’” said Rush’s Dr. Edward Hollinger.

His son, Daniel, donated the kidney donor.  Doctors say Daniel is in good condition and could leave the hospital Thursday.

They say the superintendent will probably be released from the hospital this weekend then spend at least three weeks recovering at home.

Johnson underwent surgery Wednesday morning. Johnson arrived at Rush University Medical Center at 6 a.m. for the operation.

Johnson’s 25-year-old son is donating one of his kidneys to his father.

Johnson disclosed in January after suffering a public dizzy spell that he has battled for decades a potentially life-threatening inflammation of his kidneys and was on a waiting list for a kidney transplant.

Johnson is expected to be back working at police headquarters within three to five weeks.