The visitors are firmly rooted in midtable after a mixed first half of the season, but could still mount an unlikely playoff push, considering they are only seven points off the top seven.
Match preview
Orient are way out in front at the top of the league standings, four points clear of nearest side Stevenage, but with a game in hand at their disposal.
Considering that the O's are 14 points ahead of fourth-placed Barrow, it would take a monumental change of form for them not to secure promotion back to the third tier one way or another this season, after an incredible start.
Richie Wellens has ensured his side are defensively sound first and foremost, conceding just 12 goals in 20 games, the best record in the league, with only four of these goals coming at the Breyer Group Stadium.
In their last six league outings, Orient have picked up four clean sheets, while also winning their last three games, against some difficult opponents to boot.
The O's were resounding 3-0 winners against seventh-placed Bradford City last time out, following on from a 2-1 away win against Stockport County, who were undefeated in seven games before Wellens' side came to town.
Sutton's start to the season has not quite been as spectacular as their opponents', firmly amongst the chasing pack for the playoffs, but showing no real signs of being able to reach them, due to inconsistent form.
The U's have failed to win two league games in a row since the beginning of September, before going on a terrible run of just one win in nine games, starting from later on that month.
Despite that run of form, the home record of Matt Gray's side has actually been very good, boasting the fifth-best record on their own patch in the league.
However, Saturday's trip to the league leaders is made even more difficult by the U's' struggles on the road, only recording one win on their travels in the league all season, dating back to a 1-0 victory at AFC Wimbledon in October.
Last time out, Sutton dominated proceedings against Colchester United, recording seven shots on target, compared to zero being registered by their opponents, and they just about managed to get over the line, winning 1-0 courtesy of a first-half Rob Milsom penalty.
Leyton Orient League Two form:
W
W
L
W
W
W
Leyton Orient form (all competitions):
W
L
L
W
W
W
Sutton United League Two form:
D
L
L
W
D
W
Sutton United form (all competitions):
L
L
W
L
D
W
Team News
Richie Wellens is unlikely to ring the changes, considering the recent form of his side, and he may name an unchanged lineup for the visit of Sutton.
Dan Nkrumah joined Welling United on loan last week, aiming to get back to full fitness after a knee injury, so he will be unavailable, while the same applies to Anthony Georgiou, who has headed to Yeovil Town after a hamstring problem.
Top scorer Paul Smyth has scored eight goals this season, and is set to keep his place in a front three, joining Charlie Kelman and Theo Archibald.
There are no fresh injury concerns for Sutton, with Alistair Smith now back to full fitness after a two-month absence, and he is set to accompany Craig Eastmond in the centre of midfield.
Will Randall is the U's' top scorer this season, with five goals, the only player in the squad to have amassed more than two, and he should play at left-wing, with Josh Neufville on the opposite flank, in a 4-4-2 system.
Leyton Orient possible starting lineup:
Vigouroux; Brown, Beckles, Happe, James; Pratley, Moncur, El Mizouni; Archibald, Smyth, Kelman
Sutton United possible starting lineup:
Rose; Boldewijn, Kizzi, John, Milsom; Neufville, Eastmond, Smith, Randall; Bugiel, Wilson
We say: Leyton Orient 4-0 Sutton United
Leyton Orient have emerged as promotion favourites this season with an outstanding run of form, and they should be able to breeze past an inconsistent Sutton side.
The O's were 3-0 victors against promotion-chasing Bradford last time out, so they could go one better, and romp him to a comprehensive victory.