Carlyle was one of handful parties vying for a minority stake in the Old Trafford club, the report said, adding that the exact details of the proposal, including the investment amount and deal structure, were yet to be finalised.
Carlyle and Manchester United did not immediately respond to a Reuters request for comment.
United's American owners, the Glazer family, launched a formal sale process late last year and have received several bids, including from Qatar's Sheikh Jassim Bin Hamad Al Thani and British billionaire Jim Ratcliffe.
Sports industry news site Sportico reported earlier this month that Manchester United would accept a third round of bids from prospective buyers at the end of April.
The Glazers bought Manchester United in 2005 for 790 million pounds in a highly leveraged deal that has been criticised for loading debt onto the club.
