Balotelli, 19, is at the centre of a tug of war between rivals United and Manchester City. Sir Alex Ferguson is believed to see the Italy youth international as the successor to Cristiano Ronaldo and is prepared to outbid the Blues and offer £25 million.
Inter president Massimo Moratti is understood to only be prepared to do business for £33m. With United unwilling to reach that figure, a part exchange including Macheda could appease the patron.
The Lazio youth product only made five starts for United last term due to a recurring groin injury. Ferguson still rates the youngster highly, however, and would be reluctant to send him packing to Inter even if Balotelli was signed in return.