But rescuers said Thursday afternoon they had changed their focus and now believed they were undertaking a recovery effort.
The missing man fell into the current while trying to rescue his dog.
The search for the man began in the late afternoon Wednesday near Lawrence Avenue after the man went into the river and disappeared.
Anmar Atiyah was there when the accident happened.
Atiyah and a man he had just met named Peter, were walking their dogs.
When Peter's dog went into the river Atiyah watched in horror as the 35-year-old jumped in after his pet.
Atiyah tried to help.
"For sure I was panicking, something. and even I was trying to yell his name, but he didn't reply or say anything," Atiyah said.
He could tell immediately conditions were extremely dangerous.
"Believe me, yesterday the water so strong going one way, cold, so heavy," he said.
The dog managed to make it to safety, but the man has not been found.
The water level is high moving faster than normal due to this week's heavy rains.
The Toronto Conservation Authority says the river will probably return to normal over the next 24 to 36 hours.