Emergency services were forced to rush to The Wicker yesterday after residents saw a man swimming in the river.
Police rushed to Lady's Bridge at around 12.45pm on Friday after residents reported seeing a man swimming in the River Don.
Eye-witnesses said officers were 'frantically' looking into the river as ambulances pulled up on the street.
Motorists reported delays on the street as emergency services blocked the road to respond to the incident.
South Yorkshire Police have been contacted for a comment.
More to follow.