Manchester United defenders Marcos Rojo and Paddy McNair suffered injuries against Southampton and will miss Wednesday's third-round League Cup clash against Ipswich Town at Old Trafford, manager Louis van Gaal has confirmed.

The duo's unavailability comes at a bad time for the Dutchman with left back Luke Shaw also ruled out for six months after a horrific leg break in the 2-1 Champions League defeat at PSV Eindhoven last week.

"Rojo has a hamstring injury and Paddy McNair has a minor injury," the manager told the club's website.

The injuries to two more defenders mean that Phil Jones could make his first appearance of the season for United, despite not being fully fit.

The 23-year-old has been sidelined with mild thrombosis -- a blood clot -- but has been included in the squad and will be on the bench for the tie against the Championship side.

"I have to admit that because of the injury of three defenders (including Luke Shaw), I shall have Jones on the bench but he is not fit," Van Gaal said.