Newcastle's Beye: Everyone playing for their futures
He said: "The manager has choices here. All we can do is stay fit and work hard.
"At the moment, we are going through a lot of difficulties, and we need to have everybody.
"Nobody can take their place in the team for granted."
Beye played his first game for Keegan in last weekend's 4-1 defeat at Aston Villa after he returned from African Nations Cup duty with Senegal.
Beye is keen to put his international disappointment - Senegal went out at the group stage after they lost to Angola and drew with Tunisia and South Africa - behind him and help his club out of their current difficulties.
He said: "I have been playing in Ghana for my country, now I want to play here and do a job for the team and the manager.
"I am confident in myself to do that and I am ready for the fight which lies ahead.
"The way the tournament ended for me was a big disappointment. Now it is important for me to play well for Newcastle.
"We need these two weeks to prepare for the match against Manchester United. It gives us the chance to get our minds on the job and put things in place.
"For people like myself, Oba, Geremi and Abdoulaye, we probably need these two weeks to re-acclimatise after playing in Africa.
"We are already preparing hard for the next league game."