After their third-round win against Championship side Burton, Mourinho suggested English sides in Europe could benefit by not playing in the Carabao Cup.
The 28-year-old, an £11m signing from Las Palmas, has spent most of his time in south Wales on the bench, with just one Premier League start and two in the EFL Cup. Five defeats in nine has seen Swansea sink to 15th in the league with eight points, level with Everton in 18th.
Manchester United have hit a poor run in recent weeks as they are winless in their last two Premier League games.
Paul Clement has confirmed that Wilfried Bony won't feature, with Nathan Dyer, Wayne Routledge or Oliver McBurnie named as the possible replacements. Sergio Romero will replace David de Gea between the sticks, while Matteo Darmian and Daley Blind are expected to come into the full-back positions.
However, other key squad members have however travelled, including Romelu Lukaku, Henrikh Mkhitaryan, Marcus Rashford, Anthony Martial and Nemanja Matić. Paul Pogba, Marouane Fellaini, Zlatan Ibrahimovic, Marcos Rojo and Michael Carrick remain on the sidelines for Man United. Last weekend, the team was again defeated in native walls, this time from "Leicester" 1: 2.
As mentioned, neither team would have listed the EFL Cup as high on their list of priorities this season. With that in mind, Mourinho's side should march into the next round without too many problems.