The transfer of the Italy international will see 21-year-old striker Ishak Belfodil move in the opposite direction.
Negotiations were conducted on Monday between Parma official Pietro Leonardi and his counterparts at Inter and it appears things went in a positive way.
Agent Beppe Bozzo claims the switch is likely to be concluded before the end of the week.
"Wednesday or Thursday the negotiation will be closed", Bozzo told Parma Today.
Cassano only joined Inter in August 2012 from rivals Milan but the 30-year-old forward looks set to sign for the seventh club of his career.