The two teams are meeting for the very first time in the FA Cup and for the first time in any competition since January 2017 when they played out a 2-2 draw in League One.
Match preview
Gillingham have progressed to the FA Cup third round for second successive season after beating non-league Hereford United and League One side Charlton Athletic by 2-0 scorelines in the first two rounds.
Stephen Clemence was in charge for both fixtures and has overseen a total of 13 games since his appointment as Gills manager in November, winning six times including back-to-back 1-0 victories in League Two against Sutton United and Colchester United either side of last weekend.
Left-back Scott Malone netted the decisive goal in both matches to help Gillingham climb to 10th place in League Two, just one point behind seventh-placed AFC Wimbledon who occupy the final playoff spot.
Gillingham now shift their focus to a glamour tie in the FA Cup, a competition close to Clemence's heart as his late father Ray Clemence won England's most prestigious piece of silverware twice as a player with Liverpool (1974) and Tottenham Hotspur (1982).
The prospect of Gillingham going deep into this season's competitions is slim, though, as they have lost six of their last seven FA Cup third-round ties as well as nine of their previous 11 encounters with Premier League opposition.
Since replacing Paul Heckingbottom in early December, Chris Wilder is yet to make the desired impact in his second spell in charge of Sheffield United, who have won just one, drawn one and lost four of their last six games.
The Blades were put to the sword 2-0 by reigning Premier League champions Manchester City last weekend - their 15th league defeat of the campaign - and they remain rooted to the foot of the table, seven points adrift of safety.
Sheffield United will welcome this weekend's break from the Premier League as they have had a decent crack at the FA Cup in recent seasons, progressing as far as the quarter-finals twice and the semi-finals once (last season) over the last four years.
The Blades have not won away from home in any competition since May last year, but they will be confident of success on Saturday as they have advanced from 18 of their last 19 FA Cup ties against teams from lower divisions.
Gillingham FA Cup form:
W
W
Gillingham form (all competitions):
W
L
D
L
W
W
Sheffield United form (all competitions):
L
W
L
D
L
L
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Team News
Gillingham midfielder Jonny Williams missed the win over Colchester last time out due to a hamstring injury and it remains to be seen whether the Welshman will recover in time for Saturday's game.
Max Ehmer managed to shake off an ankle issue to start and play the full 90 minutes on Monday, and the centre-back is set to retain his place in the back three alongside Shadrach Ogie and Conor Masterson.
Tom Nichols will be hoping to force his way back into the first XI at the expense of either Oli Hawkins or Ashley Nadesan - the striker has been involved in seven goals in his last eight FA Cup appearances, scoring five and assisting three, while he has also scored twice in his last four games against Premier League teams in the competition.
As for Sheffield United, Max Lowe is facing three to four weeks on the sidelined with an unspecified injury, while youngster Sydie Peck has undergone knee surgery; both players join Chris Basham (ankle), John Egan (foot), Tom Davies (thigh) and Daniel Jebbison (illness) in the treatment room.
The Blades will also be without midfielder Anis Ben Slimane and defender Yasser Larouci as they have been called up by Tunisia and Algeria respectively for the Africa Cup of Nations.
However, Anel Ahmedhodzic and Gustavo Hamer are both available to return after serving suspensions last weekend, as is Man City loanee James McAtee who was ineligible to face his parent club.
Wilder will likely consider rotating his side this weekend, with the likes of Adam Davies, Rhys Norrington-Davies, Ben Osborn, Benie Traore and Rhian Brewster all pushing to start.
Gillingham possible starting lineup:
Turner; Masterson, Ehmer, Ogie; Alexander, Coleman, Jefferies, Lapslie, Malone; Bonne, Nichols
Sheffield United possible starting lineup:
Davies; Baldock, Robinson, Trusty; Bogle, Norwood, Brooks, Osborn, Norrington-Davies; Traore, Brewster
We say: Gillingham 0-1 Sheffield United
Rarely have Sheffield United entered a fixture this season as favourites, but Saturday's contest is one they will not be considered as underdogs, although success against a resurgent Gillingham side is not a given.