Defensively, the Red Devils are down to the bare bones, with Marcos Rojo having now joined Chris Smalling and Phil Jones on the treatment table.
Zlatan Ibrahimovic also suffered a potentially season-ending injury in the 2-1 win over Anderlecht on Thursday night to add to Mourinho's problems ahead of the trip to Turf Moor.
And the Portuguese could not hide his frustration at the situation at Old Trafford. He told reporters: “Eric Bailly has played six matches in a row - 540 minutes in a row.
"We lost Rojo, we don’t have Jones, we don’t have Smalling.
“We are in trouble and, now, we lose Zlatan too but, in attack, we have options: Rooney is coming and let’s see if Mata can also return before the end of the season. Let’s see what happens.
“Herrera plays [against Burnley]. He didn’t play on Thursday – one yellow card and he would have missed the semi-finals. I was thinking about him and [fellow substitute Marouane] Fellaini both at the same time but, because I made a change with Marcos Rojo, I couldn’t do that and he didn’t play.
“So Herrera is fresh to play. Ashley Young is fresh to play and who else? Nobody else is fresh to play! Now we need absolutely everyone and I don’t have to think about Axel Tuanzebe going to the Under-20 World Cup in Korea because maybe Axel has to come now. We need everybody.”