Roy Hodgson bemoaned the absence of Wilfried Zaha for Crystal Palace's FA Cup quarter-final defeat to Watford on Saturday.
Palace's talismanic forward struggled with a calf injury after last weekend's loss to Brighton and Hove Albion and had to sit out the 2-1 defeat at Vicarage Road.
Michy Batshuayi had cancelled out Etienne Capoue's opener but Andre Gray scored late on to seal a spot in the last four for Javi Gracia's side.
Hodgson was left to rue the Ivory Coast international's absence and admits he does not know the severity of his injury.
"We were unlucky to lose a player of Zaha's quality before the game," he told a media conference.
"We don't really want to go into an important quarter-final without players of his ability and his importance.
"He felt it after the Brighton game and didn't train during the week. It would have been an enormous risk to play him, a risk of a much more serious injury.
"With the two weeks now coming up [due to the international break], we can only hope he will recover in time when we play our next game [against Huddersfield Town on March 30].
Watford boss Gracia, meanwhile, was fulsome in his praise of goalkeeper Heurelho Gomes and insists that a final decision has not been made on his future.
Gomes – who has been restricted to appearances in cup competitions this season – has previously said that he is "99 per cent" he will retire at the end of the season, but Gracia has suggested that his playing days might not be over just yet.
"Everybody knows Heurelho is a very important player for us," he said.
"This week there were many things said about if this will be his last game or not but it's not so important to me.
"For me, the most important thing is that he's playing well, he's enjoying it with the team, and we'll see what happens in the next games and in the future as well.
"There is no clear decision yet and we will have to speak about him in the future."