League One Preview: Top two meet, Wolves host O's
The sides have not been in the best of form lately, with Orient winning one of their last five league games and Wolves winning just twice in that time.
However, they are only separated by goal difference at the summit of England's third tier and a win for either side could put them three points clear going into the second half of the season, boosting their hopes of clinching the title next year.
For third-placed Brentford, a draw between the top two would be the ideal result as it would allow them to go top with victory over visitors Milton Keynes Dons.
Mark Warburton's men have dropped only eight points at home all season, winning their last five at Griffin Park while keeping clean sheets in three of them.
However, Karl Robinson's side have won their last three league matches without conceding a goal and will be keen to close the gap to the play-off places.
At the foot of the table, Crewe Alexandra's mini revival came to an end on Thursday when they were beaten by Wolves but will avoid finishing 2013 bottom of the table with victory over mid-table Colchester United.
Fellow strugglers Notts County travel to Crawley Town, while Bristol City host Stevenage in a relegation-zone six-pointer.
The two are level on points, although Stevenage have a far inferior goal difference, with victory for the hosts potentially enough to move them out of the danger zone, provided Sheffield United are beaten by Tranmere Rovers at Bramall Lane.
Swindon Town travel to Bradford City, mindful of the five-point gap between themselves and the play-off spots, while Carlisle United go in search of their first win in three league games against Peterborough United at Brunton Park.
The league's highest scorers Coventry City could reach the 50-goal mark when Oldham Athletic visit Sixfields, while Walsall and Port Vale face Gillingham and Rotherham United respectively.
Shrewsbury Town welcome promotion-chasing Preston North End, with Simon Grayson's men tasting defeat only once on the road in League One this season - a 2-0 reversal against Peterborough in October.