Leicester are hanging onto a top-four spot after winning one of their six matches since the restart, while United are back up to seventh following back-to-back victories.
Brendan Rodgers did not hold back following Leicester's shocking 4-1 collapse against Bournemouth on Sunday, admitting that his side are nowhere near Champions League level.
From looking top-four certainties before the restart to relying on other teams to drop points, a season that offered so much for City is at risk of completely crumbling.
Leicester took the lead against an out-of-sorts Bournemouth side through a Jamie Vardy strike, but a calamitous two-minute spell saw them concede twice and lose a man.
Bournemouth took advantage of Caglar Soyuncu's dismissal by running away with the win, making it six points from the last 18 on offer for Leicester.
Yet somehow they still remain in possession of fourth place, level on points with Manchester United following the Red Devils' 2-2 draw with Southampton on Monday.
That ultimately means that Leicester's fate remains in their own hands, but they face tricky games against Sheff Utd, Tottenham Hotspur and Man Utd to conclude the campaign.
One game at a time will be the mantra for Rodgers, and indeed opposite number Chris Wilder, who has to be a contender for the Manager of the Season award.
Wilder's men have recovered from a post-lockdown slump that saw them lose two and draw one of their first three matches back by taking 10 points from the last 12.
The Blades scored a dramatic late winner against fellow European chasers Wolverhampton Wanderers last week and followed that up with a 3-0 win against Chelsea on Saturday.
As far as performances go, that display was right up there as United crushed third-place Chelsea - a result that Leicester supporters would have celebrated just as wildly.
The Yorkshire club are one point behind Wolves in the final Europa League spot and have mid-table Everton and Southampton to come after this trip to the East Midlands.
With Leicester only five points better off, even a place in the Champions League cannot be entirely ruled out for United just yet in what has been a campaign to remember.
Leicester City's Premier League form: DDLWDL
Leicester City's form (all competitions): DLLWDL
Sheffield United's Premier League form: LLWDWW
Sheffield United's form (all competitions): LLWDWW
Soyuncu is banned for this match after being sent off against Bournemouth, possibly meaning just a second Premier League start for Ryan Bennett since joining on loan in January.
John Lundstram is among those pushing for inclusion but, despite the quick turnaround in matches, Wilder is unlikely to make any changes from the Chelsea win.
David McGoldrick scored his first Premier League goals in that impressive victory and is looking to net in consecutive league matches for the first time since January 2019.
Leicester City possible starting lineup:
Schmeichel; Albrighton, Bennett, Evans, Justin; Ndidi; Perez, Praet, Tielemans, Barnes; Vardy
Sheffield United possible starting lineup:
Henderson; Basham, Egan, O'Connell; Baldock, Berge, Norwood, Osborne, Stevens; McBurnie, McGoldrick
We say: Leicester City 2-1 Sheffield United
This really is a huge game and one that both sides will be targeting victory from. Leicester's only two victories since February have come at the King Power Stadium, while United have gone four matches without an away win - losing 3-0 to Man Utd and Newcastle in that run - so we are backing the Foxes to edge this one.