Unai Emery is hoping to have a deal for Denis Suarez completed by the weekend.
Arsenal are still working on a switch which would see the 25-year-old Barcelona midfielder replace Juventus-bound Aaron Ramsey and the Welshman joining the Italian champions this month instead of in the summer.
Valderde said: “We are happy with the squad but there are always possibilities for departures for those who maybe do not feature as often.
“Those players could stay here and we would be happy or they could leave in search of more opportunities, we will evaluate all possibilities for them.
“We work internally and there is a lot of planning involved of which I am a part, but we will see how the market progresses.”
Suarez is one of two loan deals being sought by Arsenal.
Emery is confident of being reunited with the man he coached at Sevilla five years ago as Suarez has played just 17 minutes of La Liga action this season and has featured mostly in the Copa del Rey.
Emery confirmed last weekend that he wanted to take Suarez. Answering questions on the Spaniard he said: “The club is working with every situation that can help us.
“I cannot speak about individual players but I know the club is working on different possibilities if it can help us this month for our competition.
“The transfer window is difficult for the market but the club are working – if one player comes to help us then I am happy but the club is doing that and I am going to wait.”