The Whites came back from 2-0 down to draw 2-2 with their Championship counterparts two weekends ago, and a meeting with Boreham Wood or Accrington Stanley awaits the victors.
Match preview
Staring down the barrel of defeat at the Cardiff City Stadium until the third minute of second-half injury time, Leeds went into the half-time interval with a 2-0 deficit to make up after Jaden Philogene and Sheyi Ojo put the Bluebirds in the ascendancy in their FA Cup opener.
A pair of inspired substitutions from Jesse Marsch ultimately saw Leeds avoid an immediate elimination, as Rodrigo pulled a goal back in the 65th minute before Sonny Perkins levelled right at the death to add another game into the hectic winter calendar.
A cup run would be welcomed with open arms by the Leeds faithful, but Marsch has bigger fish to fry in the Premier League, with a 2-1 defeat to Aston Villa on Friday leaving the Whites 14th in the standings and only two points clear of the relegation zone.
Having failed to win any of their competitive fixtures since the World Cup break, Leeds' victory-less run in all tournaments now stands at an abysmal seven games since their dramatic 4-3 success over Bournemouth on November 5, and goal-laden affairs have been the theme at Elland Road recently.
Indeed, Leeds have scored nine goals and shipped 11 in their last four competitive fixtures at home, but they are now at risk of going out in the third round of the FA Cup for the sixth year running, having failed to progress further since their 2016-17 fourth-round exit to Sutton United.
Prior to being given the boot, ex-Cardiff boss Mark Hudson would have been ruing an 80th-minute red card to Joel Bagan in their four-goal stalemate with Leeds, with the left-back given his marching orders with 10 minutes to go as the Bluebirds failed to hold on.
That was the latest in a long line of draws for Cardiff, who also claimed a point from their weekend Championship clash with Wigan Athletic, where they were once again hit with a stoppage-time sucker punch as Callum O'Dowda's effort was cancelled out by Will Keane six minutes into added time.
Saturday's stalemate versus the Latics proved to be the final straw for Hudson, who has now been relieved of his duties after overseeing a nine-game run without victory. Coincidentally, Cardiff's most recent win also came on the date of Leeds' - November 5 - a narrow 1-0 triumph at Sunderland.
Dean Whitehead takes temporary charge of the Bluebirds, who have six draws to show from their last seven in all tournaments and sit 21st in the Championship table as a result, and they have made a habit of going out in the third round and then the fourth round of the FA Cup since 2016.
Having lost in round four to Liverpool last season, history does not favour the Championship side, although they are unbeaten in six against Leeds since suffering a 2-0 home loss in the second tier in September 2016.
Leeds United FA Cup form:
D
Leeds United form (all competitions):
L
L
D
D
D
L
Cardiff City FA Cup form:
D
Cardiff City form (all competitions):
D
D
D
L
D
D
Team News
Leeds have no fresh injury concerns to report from their defeat to Aston Villa, but Marsch could still be without a quintet of players here, with long-term absentees Archie Gray and Stuart Dallas both out of contention.
The replay is also expected to come too soon for Luis Sinisterra and Crysencio Summerville to return from their ankle injuries, while Adam Forshaw remains sidelined with a groin issue but is expected to return to training in the near future.
Perkins's late equaliser in Cardiff is unlikely to be enough to earn him a start here, but Sam Greenwood and Joe Gelhardt could benefit from some rotation alongside new signing Maximilian Wober, who is yet to start since arriving from Red Bull Salzburg.
As for Cardiff, Bagan served his suspension in the draw with Wigan and will be at Whitehead's disposal here, but Mahlon Romeo (hamstring) and Jamilu Collins (ACL) remain on the sidelines.
Bagan may be fighting an uphill battle to return at left-back following O'Dowda's goal at the weekend, where Hudson made no fewer than three half-time changes, as Jack Simpson, Joe Ralls and Mark Harris were all sacrificed.
The door could therefore be open for Andy Rinomhota and Romaine Sawyers to take their places in the starting XI, and ex-Tottenham Hotspur striker Kion Etete is an option for change up front after returning from injury.
Leeds United possible starting lineup:
Robles; Kristensen, Wober, Llorente, Firpo; Gyabi, Roca; Aaronson, Greenwood, Gnonto; Gelhardt
Cardiff City possible starting lineup:
Alnwick; Ng, Kipre, Nelson, O'Dowda; Rinomhota, Wintle; Ojo, Sawyers, Philogene; Davies
We say: Leeds United 2-1 Cardiff City (a.e.t)
Neither Leeds nor Cardiff have the ingredients for a recipe for success right now, but if Whitehead can bring the new manager bounce to Elland Road with him, a leaky Whites side could be in for a tricky evening.