The hosts saw their eight-game unbeaten streak come to an end last time out, while the visitors are without a win in their last three matches.
Match preview
Prior to their 2-1 defeat at Barnsley, Leyton Orient were flying high, riding an impressive eight-game unbeaten streak that propelled them into the playoff picture.
Their run included dominant victories over Cambridge United, league leaders Portsmouth, and third-placed Bolton Wanderers, highlighting their attacking prowess.
They also earned a creditable draw at Reading before consecutive wins against Carlisle United and Port Vale further boosted their ambitions.
However, the Barnsley defeat ended their hot streak, leaving them eight points behind sixth-placed Stevenage.
Richie Wellens's side, enjoying a strong first season in League One after promotion from League Two, currently sits ninth with 45 points from 31 games.
Now, they face a tricky test against Northampton, a team they have not beaten in their last seven meetings.
Northampton, defying expectations after promotion from League Two, have mostly held a top-half position this season.
However, recent form has been mixed, with defeats to Shrewsbury Town and Portsmouth followed by a frustrating 1-1 draw against Bolton Wanderers despite a red card for their opponent.
Currently 11th and 12 points off the playoffs, their focus has shifted to securing a top-half finish in their first season back in League One.
John Brady will know his side are underdogs in Tuesday's fixture given their opponent's recent home record, but they will be looking to continue their positive record against them and bounce back from recent setbacks.
Leyton Orient League One form:
W
W
D
W
W
L
Northampton Town League One form:
W
D
W
L
L
D
Team News
Leyton Orient will be without key defender Omar Beckles and winger Jordan Graham once again, as both players are currently nursing injuries.
In Beckles's absence, Dan Happe and Brandon Cooper are bound to continue their partnership in the middle of a back four, while Idris El Mizouni and Jordan Brown are mainstays in midfield.
Ruel Sotiriou will lead the once again, receiving support from the trio of Shaqai Forde, George Moncur and Ollie O'Neill.
For Northampton, Louie Moulden should continue in goal after replacing Lee Burge, who left the last game due to an injury.
Bowie and Louis Appere should flank Mitch Pinnock in an unchanged attack from the draw with Bolton.
Leyton Orient possible starting lineup:
Brynn; Galbraith, Happe, Cooper, James; Brown, El Mizouni; Forde, Moncur, O'Neill; Sotiriou
Northampton Town possible starting lineup:
Burge; Willis, Monthe, Guthrie; Lintott, Leonard, Hondermarck, Brough; Bowie, Pinnock, Appere