Chadwick will tonight make his third start in a Reading shirt after sealing a one-month loan deal ten days ago.
The Blades, who are challenging for promotion and still going strong in the FA Cup would have loved to have added the 22-year-old to their razor-sharp army of players but financial worries prevented them from doing so.
"I would have loved to have signed Luke Chadwick but we cannot afford him," admitted Warnock, speaking to sufc.co.uk, ahead of tonight's clash between Reading and Sheffield United.
"No disrespect to anyone but we have to look at the other end of the market and from a manager's point of view we have to work hard with what we have got rather than moaning about it."
United, like many clubs, are feeling the pinch of the ITV Digital collapse and stand to lose £1m unless they are promoted to the Premiership and win the FA Cup.
Tonight the fourth-placed Royals will do battle with the third-placed Blades in what could be a crucial tie as the end of season table begins to take place.
Warnock admitted that he is expecting a tough game from a side who have surprised a lot of people with some sterling, battling performances, helped put together by a strong defensive backbone.
The Sheffield United boss added: "It will probably be our toughest home match. They play a system that they are used to home and away, with one up front and breaking from midfield, with Salako on one flank and Chadwick on the other.
"Reading have some quality players and are very solid at the back. They have only conceded fifteen goals away from home all season, which I think is one of the best in the Division.
"We played well at the Madejski Stadium and we will have to try to break them down again tonight."