The Blades suffered a 3-0 defeat at the hands of Arsenal on Sunday evening, and now stand on the brink of a return to the Championship.
Their fate will be sealed if they lose to Wolves next Saturday, and if Newcastle United can pick up a win against high-flying West Ham.
But looking ahead to next season, Warnock has warned that things could get even worse for United if they’re not careful about how they approach the second tier.
Speaking on Sky Sports’ Football Show, he said: “You can’t take anything away from Arsenal – they were outstanding.
"I was at Leeds last week, and they went out with a fight. They challenged every single ball, the changes that they made tactically were good. I thought they were really good in the game against Leeds.
"Then you look at that performance [against Arsenal] and they did look like they went out with a whimper. Players need to reset. They’ve got to make sure that they get themselves mentally right to go themselves into a game to think, ‘I’m playing for my future’ – whether it’s at Sheffield United whether it’s to all the managers who might want to keep them in the Premier League.
"They have to reset and they have to did it quickly because you can quite easily see yourself getting relegated and relegated again if your attitude isn’t right. They shouldn’t do. They should come straight back up with that squad.”