The Tykes visit Old Trafford for a 20:00 BST kick-off, with a place in the fourth round of the competition up for grabs, and it remains to be seen if Erik will shuffle his pack.
Alejandro Garnacho came off the bench to score at the weekend and, by the reckoning of former United defender Wes Brown, the Argentina international should be one of eight changes in the Reds' starting XI on Tuesday evening.
WES BROWN'S PREDICTIONS
United XI
Heaton
Dalot
Maguire
Evans
Amass
Casemiro
Ugarte
Eriksen
Antony
Zirkzee
Garnacho
First scorer: Alejandro Garnacho
Man of the Match: Manuel Ugarte
Score: United 2 Barnsley 0
Fellow ex-Red Danny Webber has selected fewer alterations to United's line-up, but is backing Ten Hag's team to win by a clearer margin.