The Owls were due to welcome their South Yorkshire rivals to Hillsborough on Saturday October 28.
But the clash has now been pushed back a day to Sunday October 29, with the kick-off time also changed from 3pm to 1pm.
A statement released by Wednesday makes clear the decision has been made as per police advice.
The Owls have a difficult recent record against the Millers, winning only one of the last seven match-ups between the two sides and losing three of their last four.
As things stand, both sides are among the strugglers in the Championship table, with Wednesday sat in 23rd place and Rotherham in 21st.