United are being linked with moves for Roma centre back Phillipe Mexes and Napoli midfielder Marek Hamsik.
Reports in Italy claim Sir Alex Ferguson has reignited his interest in Mexes, 27, who he tried to sign from Auxerre back in 2003.
The Frenchman, however, is settled in Rome and the rumour may have more to do with his contract renegotiations as his current deal expires in 2011.
United scout David Williams has also been keeping close tabs on Hamsik for Ferguson, who is on the lookout for an all-action attacking midfielder with Paul Scholes likely to call it a day soon and Anderson having failed to emerge as a consistent performer before his injury.
The 22-year-old Slovakian has been watched several times and would cost between £15-20million to bring to Old Trafford.