Herrera had been struggling in recent weeks with a muscle complaint and then appeared to pick up a hamstring injury 17 minutes into Wednesday's game at the Ramon Sanchez Pizjuan.
Unable to continue, the player was taken off, allowing Pogba the chance to get involved having previously been left on the bench in something of a shock decision made by Jose Mourinho.
The France international had originally been overlooked in favour of Scott McTominay, who filled the final United midfield spot in Andalusia.
He had also missed out at the weekend due to an illness, giving McTominay the chance to shine in a 2-0 defeat of Huddersfield Town.
Pogba's form has dipped of late and has reportedly seen his relationship with Mourinho become strained as a result.