Information and team news ahead of the O's trip to Fratton ParkThe O’s will be looking to bounce back from last weekend's home defeat to Barnet when making the trip to Portsmouth tomorrow.
Andy Edwards' side were unable to make it four games undefeated at the Matchroom Stadium when losing 3-1.
Ricardo Santos' quickfire double put Orient on the back foot, and despite Paul McCallum pulling one back, a late third from Curtis Weston sealed the victory for the Bees.
Going into the game the O's lie in 21st place with 25 points from as many games, while Paul Cook's Pompey hold fourth spot with 42 points.
The Fratton Park hosts lost 3-1 last time out to league leaders Doncaster Rovers in a televised encounter last Thursday. Former O John Marquis netted twice in the win and Tommy Rowe once despite Kal Naismith having made it 1-1 at half time for Pompey.
Portsmouth have won six of their 11 home league games to date with defeats suffered against Doncaster (2-1), Notts County (2-1) and Stevenage (2-1).
AHEAD OF THE GAME
Manager Andy Edwards on facing Portsmouth tomorrow – here
Midfielder Sammy Moore on returning to the O's ahead of the Pompey trip – here
Midfielder Sandro Semedo will be available to boss Andy Edwards once again after recovering from a toe injury which ruled him out of the Barnet game.
The O's are boosted by the early return of midfielder Sammy Moore from his loan spell at Dover Athletic and he can go straight into the squad for the trip to Fratton Park
Striker Sam Dalby (ankle) remains ruled out, and other than long-term absentees Robbie Weir (ACL) and Liam Kelly (hamstring) the O's are injury free.
SKY BET BETTING (correct at the time of writing)
The O's are 7/1 outsiders to come away with all three points from Fratton Park tomorrow, with Pompey 2/5 favourites. The draw is available at 18/5.
Orient emerged 1-0 victors there last season thanks to Jobi McAnuff's strike, and a repeat of that scoreline can be backed at 18/1.
All of Pompey's three home defeats finished 2-1 and a fourth is available at 25/1, and O's former Pompey loanee striker Paul McCallum is 10/1 to net the opener.
Gary Roberts leads the way for Paul Cook's side at 7/2, closely followed by Conor Chaplin and Michael Smith at 4/1.
Can’t make the game tomorrow? Follow live updates through the official Twitter feed. For commentary on the game, listen to BBC London’s Dave Victor on Orient PlayerHD.
Match report and reaction following the game will appear on leytonorient.com.