Netherlands boss Louis van Gaal is doubtful that Memphis Depay and Steven Berghuis will be fit enough for Sunday's Nations League Group A4 decider against Belgium.
The Oranje cemented their position as group leaders on Thursday with a 2-0 win over Poland thanks to goals in each half from Cody Gakpo and Steven Bergwijn.
That result means they only need to avoid defeat to Roberto Martinez's side to progress to the Finals next June.
Berghuis replaced the injured Teun Koopmeiners inside the opening five minutes at the PGE Narodowy in Warsaw, but the forward was later withdrawn for Kenneth Taylor, while Depay limped off in the 52nd minute to be replaced by Vincent Janssen.
Van Gaal had good news on Koopmeiners' condition, but the Netherlands boss was not optimistic about Depay and Begrhuis' chances of featuring against the Red Devils.
"I understand that Teun was already feeling a bit better, and I replaced Frenkie [de Jong] as a precaution. He had some tension on the muscles, but he expects to play, and he knows his own body," Van Gaal told NOS.
"I don't think Memphis will play on Sunday and neither will Berghuis. It's a back injury and that usually lasts longer than a few days."
Gakpo, who was linked with a move to the Premier League during the transfer window, has started the season in fine form for PSV, scoring eight goals in seven Eredivisie games.
The 23-year-old continued his momentum on the international stage as well, stroking home his third goal for his country early on.
He played in a more central role than he is accustomed to at club level, and Van Gaal believes that is where his future might lay.
"I thought that Gakpo performed his duties well both in possession and out of possession," the head coach added.
"It was a good lesson for him and a good development. He wanted to play from the left, but for me, he has everything to become a good 10.
"He scored again, that's also important. It was a world-class goal. I jumped off the bench too. I don't normally do that. It was a top goal."