Sunderland are currently seven points away from safety.
Allardyce has rotated his squad in search of finding the winning formula at Sunderland, but he has not picked up the wins he was hoping for.
“Everybody has had a go, everybody has had a chance and the time has come for the reckoning,” Allardyce said.
“The reckoning means that players might not get another chance.
“They might be surplus to requirements. I’ve said that to players. It has been done and said.
“Am I going to continue to be patient with them or are they going to prove they’re capable of playing week in, week out and get us out of trouble? Everybody has had a turn.
“Everybody sits in this room and looks me in the eye and when they’re not playing they say, ‘Well, why are you not picking me?’
“Now they’ve all had a turn, so I can say to them, ‘I’m not playing you because when I did you weren’t good enough’.
“That’s the hard reality. They don’t like to hear it, but it’s a sad fact.”
Sunderland have improved under Allardyce, but their progression has not been rapid enough to get them out of the relegation zone.
The Wearsiders have simply conceded too many goals to be successful.
Allardyce has already expressed a desire to tighten up Sunderland’s backline, but he is under pressure to make an impact quickly.
Sunderland are already seven points away from safety, with their next fixture coming against Liverpool later this evening.