The 10-storey complex is due to be built next to United's home ground, despite initial concerns from the former Premier League champions.
Reports had emerged claiming that the 37-year-old was keen to install a pitch along with a retractable canopy and bar.
Projects director from Red Property Service Anthony Kilbride told the Manchester Evening News: "The roof was to be used on match days and we decided to utilise it with something a bit more interesting.
"I can not think of a more iconic location to play five-a-side football. We hope to attract families and kids to use the pitch, it will not be exclusively for hotel guests."
The hotel is expected to be open in time for the start of the 2014-15 campaign.