Rangers and The Blades played out a 1-1 draw at Bramall Lane on Sunday afternoon and will replay at Loftus Road on Tuesday, January 12th.
The winners will go through to the Fourth Round where they will meet Bolton at The Reebok Stadium on the weekend of 23rd/24th January.
Full Fourth Round Draw:
Tottenham v Leeds United
Tranmere/Wolves v Crystal Palace
Aston Villa v Brighton
Preston v Chelsea
Portsmouth/Coventry v Sunderland
Bolton v Sheffield United/QPR
Accrington/Gillingham v Fulham
Everton v Nottingham Forest/Birmingham
West Brom v Plymouth/Newcastle
Scunthorpe United v Manchester City
Notts County/Forest Green v Wigan Athletic
Stoke City v Arsenal
Bristol City/Cardiff City v Leicester City
Millwall/Derby v Brentford/Doncaster
Reading/Liverpool v Burnley
Southampton v Ipswich