This will be the first meeting between the two teams since the 2006/07 Premier League. Both teams won their home matches to nil when they met.
Sheffield United have lost both League Cup matches against the Hammers, failing to score in both and conceding seven.
The Hammers have won nine of their last 12 League Cup matches at home, losing the other three including last season’s semi-final to Manchester City.
The Blades' win over Mansfield in the opening round was their first in eight matches (D2 L5) in this competition.