West Ham boss Julen Lopetegui admits the uncertainty surrounding the transfer window might be affecting his players.
The Hammers have brought in eight new signings but now need to let some players go in a bid to balance the squad.
Kurt Zouma is still trying to engineer a move the the Middle East while the likes of Maxwel Cornet, Nayef Aguerd and Danny Ings could also be surplus to requirements.
"In this time before the market closes, for everyone it's still not certain who might come and go," said Lopetegui.
"We have to adapt, but the competition is tough. We've tried to adapt with the new players, and we have to balance everything and try to be competitive.
"It's true that you have to keep competing in the market while working towards games.
"Once the market is closed I think the players are fully focused, but we have to adapt. For sure I would prefer the market to be closed before the start of the season."
Lopetegui gave full debuts to Max Kilman and Guido Rodriguez, and brought on fellow new signings Niclas Fullkrug, Crysencio Summerville and Jean-Clair Todibo, in the opening-day defeat by Aston Villa last weekend.
This Saturday they head across London to face a Crystal Palace side also beaten 2-1 in their first match of the season.
"Villa is in the past, and I think we have to look forward," added the Spaniard.
"We have another big challenge against Crystal Palace, but we believe in ourselves and we have to show our qualities both with and without the ball in a difficult stadium.
"We have seen their first game. They are going to try to use the manager's way to play, and both teams are going to focus on their strengths. We have quality too, so we have to believe in ourselves."
Aaron Wan-Bissaka is in line to make his full debut against his former club having made a £15million switch from Manchester United earlier this month.
