 In July 2009, Treacy joined Sheffield United on a six-month loan deal, making his début for the Blades in a 0–0 draw with Middlesbrough on the first day of the 2009–2010 season.He soon followed his début up with two assists for the Blades against Watford the following week and a stunning long range goal three days later in a midweek match against Leicester City.After starting the season as a regular in the Blades side he had dropped out of the team by November and terminated his loan stay early to return to Blackburn in mid December.