Reading, meanwhile, have suffered four successive defeats and have slipped to sixth in the league table.
Millwall have found it difficult in recent weeks to win matches at The Den and they ground out their fourth home draw against Cardiff City on Saturday.
Gary Rowett's side have now drawn three successive league matches and six in total this campaign - only Middlesbrough have drawn as many games as the Lions at this stage of the season.
Millwall have only lost twice in the league and if they had converted their draws into wins, they would be sitting in a much stronger position in the table.
The hosts have found a way of defeating Reading in recent seasons, winning four of their last six matches, as many as they had in their previous 23 against the Royals.
Rowett has also won five times against Reading in his managerial career, only beating Bolton Wanderers and Brentford on more occasions.
Securing three points on Wednesday night could see Millwall move as high as seventh in the table, one place and one point behind the Royals.
Reading manager Veljko Paunovic has come to realise the difficulty of the Championship, as his side have suffered four consecutive league defeats – losing 4-2 away at Bournemouth last weekend – after going their first eight matches unbeaten.
In just under a month, the Royals have gone from being six points clear at the top of the table to two points behind current table toppers Norwich City and now sit in sixth place.
Reading had conceded only one league goal from their opening seven league matches, which was the best record of all 92 football league clubs, but since then the Royals have conceded 15 goals, which is more than any other side in the top four divisions.
Reading head into Wednesday night's fixture with a poor record against the Lions, as they have lost each of their last three away league games at The Den.
Reading are also looking to win back-to-back away league games in London for the first time since April 2014, having beaten Charlton Athletic back in July.
A win against Millwall could see Reading move back to the top of the Championship if all of the current top five fail to secure three points in midweek.
Millwall Championship form: DWLDDD
Reading Championship form: WWLLLL
Forward George Puscas is unlikely to start the match as he is nursing a knock that he picked up on international duty with Romania.
Millwall possible starting lineup:
Bialkowski; Hutchinson, Cooper, Wallace; Leonard, Woods, Thompson, Malone; Wallace; Smith, Parrott
Reading possible starting lineup:
Rafael; Esteves, Morrison, Moore, Richards; Rinomhota, Laurent; Meite, Olise, Ejaria; Joao
We say: Millwall 1-2 Reading
Both sides will be hoping for a victory on Wednesday in what should be a tight contest. Reading have scored eight goals in their last three away games but only managed to win one of those matches. Their firepower however should be strong enough to break down Millwall's backline and help secure their first win in five.