Pau Victor and Dani Olmo traveled with the squad to Saudi Arabia for the Spanish Supercopa, but cannot play as their registrations have been blocked due to the club's financial issues.
Flick said ahead of the semifinal against Athletic Bilbao: "I don't think it will happen tomorrow, but we will wait. The only thing we can do right now is wait. As I said before, it's not so easy for us not to have two very important players for us.
"They have improved a lot. Dani Olmo is an excellent player, of course we miss him. But we have to keep going. Of course it will affect us, but this will give us the opportunity to be closer as a team. We have to show that we are a team.
"What I can say is that we know what the situation is and how huge this club is. When you know that, you sign no matter what. It's great to be able to work with people like that."
Omn facing Athletic, he continued: "Playing against Athletic is always difficult. They are a very good team, they have very good players and a very good philosophy. It's a pleasure to watch them play. They have very fast players and they play very well. It will be a very good match.
"I feel that the team is ready and has the strength to focus only on this. We have to focus on tomorrow's game and win it. In the end, when we win titles, it is very important for us and means a lot. We are ready to show our worth by playing a very good game."