A run of three defeats from their last five outings in the Premier League has seen the Bluebirds drop to 17th in the table.
With that in mind, Marshall has urged his side to get the better of his former club, who he believes are direct competitors to Cardiff.
"It's a significant match for me against a club I played for, but it's huge for us as a whole. It's important we do well against teams around us," he told Wales Online.
The Canaries are one place and point worse off than their weekend visitors.