The Blades have completed 11 league matches unbeaten (and hope to extend that at Chesterfield in 8 days time), the United will take a break from League One football.
United have to go all the way back to 1981 when the Blades last exited the FA Cup before the Third Round stage. This was against Non-League Altrincham and having fought out a heavy 2-2 battle at Bramall Lane were thumped 3-0 in a replay.
Sheffield United extended their unbeaten Sky Bet League One run to 11 games by beating managerless MK Dons 2-1. Stefan Scougall was the star of the show for the Blades as he scored the first and then set up Billy Sharp's second-half winner, which meant the Dons' life after Karl Robinson ended in defeat. The tone was set in just the fifth minute when Scougall swept home from eight yards following good work by John Fleck from a recycled corner.
Chris Wilder's men had further chances to go in front but Daniel Lafferty headed wide and Fleck could not keep a low shot on target. And that allowed the Dons, under the caretaker stewardship of Richie Barker following Robinson's exit earlier in the week, to get back in the game as they levelled in the 49th minute when Darren Potter drilled home from the edge of the area. But the Blades are a different breed under Wilder this season and they won it midway through the second half when Sharp finished from close range after fine work from Scougall on the byline.
Sheffield United striker Matty Done remains sidelined for the home FA Cup tie against Leyton Orient due to a broken jaw. Done sustained the injury in the recent draw at Bradford and missed last week's home league win against MK Dons.
Boss Chris Wilder has hinted at resting several players after the Blades extended their unbeaten league run to 11 games last week. Midfielder Stefan Scougall is expected to continue after returning to the side against MK Dons and striker Caolan Lavery could finally make his first start for the club. They will be however without star defender Ethan Ebanks-Landell after parent club Wolverhampton Wanderers refused permission to allow him to play in the FA Cup.
Since losing the 2014 Play-Off Final, having leading Rotherham United by two goals to nil at half-time, the O's have fallen to the rotten curse which strikes most losing finalists. Twelve months on saw the Londoners lose their League One status.
Their new Italian manager Alberto Cavasin hasn't had a great start to the season either, whilst there is still a long way to go, they are currently second from bottom and starring Non-League football in the face. With key fixtures coming up against Colchester, Blackpool and Exeter, an early FA Cup exit might not be such a bad thing.
Leyton Orient striker Jay Simpson could return to the starting line-up for the O's trip to Yorkshire. The 27-year-old was named on the bench for their game against Crewe last weekend after returning from injury while new signing Michael Collins is seeking to make his debut for the club.
Yvan Erichot, Aron Pollock and Paul McCallum remain injury doubts for the game. Loanee Harry Cornick remains sidelined with a groin injury.
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