On Friday, manager Ole Gunnar Solskjaer confirmed De Gea is back in the UK but couldn't clarify whether he will be available for selection.
"Yeah, David is back in Manchester. He is quarantining or self isolating," according to the United boss.
"He's just touch and go for Sunday, I think. I can't really know when he came back, so I'm not really sure if it was Monday or Tuesday that he arrived back in Manchester."
Against West Ham on Sunday, Dean Henderson could yet keep his place though after his manager confirmed United number one De Gea hasn't trained with the team.
"He's not training with us anyway," he added. “It's different if you travel away and compete so, no, he's not been training since he came back."