Warnock suffered what appeared to be a rib injury, and was physically sick as a result.
He was substituted immediately for Chris Baird, and taken to hospital after the game.
Warnock has since given an update, using Twitter to communicate that his visit was just a precaution.
Thanks to the paramedics @SheffieldHosp who helped me today. Lovely people and doing a great job. Thanks again!— Stephen Warnock (@StephenWarnock3) December 6, 2015
Feeling a lot better now thanks. Freak collision caused me to vomit and feel unwell. Precautionary visit to the hospital.— Stephen Warnock (@StephenWarnock3) December 6, 2015
Warnock had played 90 minutes in three consecutive games prior to yesterday's game, which ended as a 0-0 draw.
The result means Derby stay unbeaten in their last three games since losing the East Midlands derby to rivals Nottingham Forest, and there is a good chance Warnock is available for their next game, at home to league leaders Brighton and Hove Albion.