Manchester United collected two more injuries from their FA Cup win at Yeovil Town.
Rafael has a suspected fractured cheekbone, while England international Luke Shaw sustained an ankle problem.
"Rafa has a fracture, so it's not looking good, and Shaw has an ankle problem," manager Louis van Gaal told MUTV. "I had to change, and I don't have more defenders, so I have to change the shape also.
"Rafael had a fresh injury so it was fantastic that he had the guts to play through. He has a fantastic mentality, it's unbelievable. But I had to change him and Shaw because they aren't 100 per cent fit.
"I put a midfielder extra in and, because of that, maybe we had more ball possession in the second half, and we had more patience.
"We have to change from five to four, we played four in midfield in the second half, then we played better and we more patient, we kept the ball better also and, because of that, we could score the winning goal."