Citing police communications, the apparent accident happened around 12:49 a.m. at the Loyola Red Line station, 1200 West Loyola Avenue, in Rogers Park.
According to police dispatch, the injured man fell on the northbound tracks.
At the time of this report, information regarding the commuter's condition wasn't immediately available.
Photo credit: CTA
UPDATE: An officer at the scene said the patient, who was transported to St. Francis Hospital in Evanston, Illinois, was seriously injured.
"It's not looking too good," said the officer.
Investigators believe the incident was an accident.