The Blues will be looking to build on their excellent away victory against Bristol City following an underwhelming start to the season.
Aitor Karanka may decide to hand Alen Halilovic his first start after his impressive 20-minute cameo on Saturday. Combative midfielder Maikel Kieftenbeld could keep his place in the side following his energetic display at Ashton Gate. However, Karanka may bring veteran Mikel San Jose back in the Dutchman's place following his rest in Saturday's fixture.
Adam Clayton currently seems the only doubt for the visitors, the midfielder is still recovering from an ankle injury. Josh McEachran is back on the pitches following his lengthy spell on the sidelines but Wednesday may be too soon for his return to the first team.
Cabral, Holmes, Morrison, Moore, Richards, Laurent, Rinomhota, Meite, Semedo, Olise, Joao.
Etheridge, Colin, Dean, Friend, Pedersen, Sunjic, San Jose, Sanchez, Halilovic, Bela, Hogan.
The hosts come into this one unbeaten in their last four (two wins, two draws). They currently sit in third but a victory against Birmingham and other results going in their favour would see them return to the top of the table.
The form of striker Lucas Joao has been phenomenal this season. The Portuguese forward has been able to take his game to the next level and he is now one of the most potent goalscorers in the division. He is also provided excellent service by teenage starlet Michael Olise, who has also been one of the league's shining stars this season. These two players alone come into this game in exceptional form, something Birmingham will need to be switched on for.
As for the visitors, their recent period of games have been frustrating for everyone associated with the club. They have thrown away leads at home to Barnsley and Wycombe Wanderers as well as dull stalemates with Millwall, Luton Town and Coventry City.
Yet, a different side appeared to emerge on Saturday after Karanka scrapped the 3-5-2 formation and returned to his usual 4-2-3-1 setup. His side went toe-to-toe with Bristol City, a side challenging at the top and bested them like teams had been doing to them this season. They showed fighting spirit in chasing the ball, being the first to second balls and ultimately earned the win they deserved.
When they have confidence Birmingham are a dangerous side when they attack and Reading should not underestimate them.
Ones to watch
Reading: Lucas Joao
The in-form striker already has 11 league goals to his name already this season and it has already been mentioned about his potency in front of goal. He will have a challenge on Wednesday facing a defence which has already kept six clean sheets this season but; Birmingham will be facing a striker who possesses more threat than the forwards they have competed against so far this season.
Birmingham: Jeremie Bela
His performance against Bristol City was the best he has played this season. The player that made a great impact last season seemed to be back once more. His pace and his quick feet can cause any defence problems when he is switched on. Both he and Ivan Sanchez have added some much-needed flair to the Blues' flanks. Bela's ability in dead-ball situations are very dangerous. Reading will know this from the sublime free-kick he scored in this very fixture last season. The winger has already provided four assists this season. His free-kicks and corners are a real threat for Reading to deal with on Wednesday.
How to watch
You can watch the match through iFollow for Reading fans unfortunate to not be in attendance (£10) or via BluesTV for the visitors (£10).