Naseeruddin Shah's son Imad, 20, was found lying injured on railway tracks in Mumbai on Thursday, police said.
He was found on the tracks near the Lower Parel (in central Mumbai) station at 8.50 am with injuries to his forehead, and was rushed to government-run Nair Hospital immediately.
"We suspect he might have fallen off a local train," a railway police official said.
Imad was later shifted to the Hinduja Hospital in Mahim (a Mumbai suburb) and kept in the intensive care unit.
In the hospital, Naseer appeared distraught, as he awaited the results at the MRI centre, along with his family and friends were with him.
Actor Akash Khurana, who was with Naseer at the time, said, "Imad is fine. We are awaiting his report."
A case regarding the incident has been registered in the Mumbai Central Railway police station.