McAtee helped the Blades to win promotion to the Premier League last season and returned to Bramall Lane just before the summer transfer window shut.
Manchester City were planning to keep hold of McAtee after selling Cole Palmer to Chelsea, but he made a personal plea to depart on loan.
The Cityzens let him speak to Leicester boss Maresca about a possible switch to the King Power Stadium, not least as they were concerned a move to Sheffield United would pitch him into a relegation scrap.
McAtee insisted on the Blades though and got his loan return to Bramall Lane.
The 20-year-old midfielder is again expected to be a key man under Sheffield United boss Paul Heckingbottom.
The Blades grabbed a 2-2 draw at home against Everton on Saturday to register their first point of the Premier League season.
They next face a tough trip to a resurgent Tottenham Hotspur under Ange Postecoglou.