The first meeting between the sides will now take place at 3pm on Sunday, September 4 in Hull due to the Super League clash between the city's two rugby league sides - Hull KR and Hull FC - on Saturday, September 3.
Hull will play Watford at 3pm on Sunday, December 11 to avoid a clash with the FIFA World Cup quarter-finals in Qatar. The last eight ties are scheduled to take place on December 9 and 10.
The Blades' home clash with Hull has been moved forward to to Friday, January 20 at 7.45pm due to Sheffield Wednesday playing at home on Saturday, January 21.
On Monday, United announced that their New Year's Day clash at QPR has been rearranged, following a mutual agreement between the two clubs.
The fixture will now take place at Loftus Road on Monday, January 2 with a 3pm kick-off.
Hull also announced yesterday that their home clash with Birmingham City in October has been moved to Sunday, October 16 at 3pm.