The 22-year-old midfielder is thought to be valued at £10m by his club. Sir Alex Ferguson is keen to build a squad capable of challenging for the Premier League title for the next five years at least, and he's focused on signing young players.
United scouts have been watching on-loan forward Angelo Henriquez at the DW Stadium, and have been impressed by the performances of Ireland international McCarthy.
The young midfielder fits the profile of a Manchester United signing, as much like Wilfried Zaha he's young enough to retain sell-on value.
McCarthy moved to relegation strugglers Wigan from Scottish side Hamilton Academical four seasons ago, but only just signed a new five-year contract with Roberto Martinez's side in 2011.
The report claims Wigan want to hold talks over another new deal to warn off interest from United, while Liverpool have also been mentioned as possible suitors.
McCarthy has 11 caps for Ireland, and has been praised for his composed passing style at the heart of a Wigan midfield that also includes James McArthur and Jordi Gomez.
The report also suggests United are interested in sending Nick Powell out on loan, and Wigan could be a potential destination for the former-Crewe star.