Russell Slade's top-of-the-table side have dropped points in each of their last two games and travel to last season's Capital One Cup finalists, who are pushing for the play-offs
Russell Slade's men have dropped points in each of their last two games, with the London club held to draws by Bristol City and Sheffield United.
Orient remain top of League One despite those slip-ups but will need to be at their best if they are to avoid defeat against a Bradford team unbeaten in their last five league outings.
Wolves are behind the leaders on goal difference and aim to bounce back from defeat to Peterborough United at the end of November as they host Milton Keynes Dons.
Brentford start life after Uwe Rosler, who left the club to join Championship side Wigan, when they take on in-form Oldham Athletic at Griffin Park in new manager Mark Warburton's first game in charge.
John Gregory will oversee his first league game as Crawley Town boss as they face a Preston North End outfit looking to stretch their unbeaten league run to nine matches.
Bristol City could move out of the relegation zone if they beat Rotherham United in Steve Cotterill's first league game in the dugout, while Shaun Derry's Notts County travel to Colchester United eyeing a win that could take them off the bottom of the table.
Crewe Alexandra's porous defence will need to improve if they are to take anything from their game with free-scoring Coventry City and fellow relegation candidates Stevenage host Port Vale hoping to avoid a third straight league defeat.
Darren Ferguson's Peterborough travel to Gillingham as they seek momentum in the promotion following the Cambridgeshire club's surprise win over Wolves.
Elsewhere, Shrewsbury Town meet Walsall, Sheffield United take on Swindon Town and Carlisle United face Tranmere Rovers.