Captain Patrick Vieira, fellow midfielder Ray Parlour and defenders Lauren and Martin Keown are all unavailable to manager Arsene Wenger as Arsenal bid to retain top place in the standings at St Andrews.
Lauren will be out for four matches and Keown three, banned for their part in the trouble between rival players at the end of the 0-0 draw with Manchester United on September 21.
Vieira, like Parlour, was suspended for one match, as well as also serving a separate one-match ban for being sent off in the incident that sparked the trouble when he kicked out at Ruud van Nistelrooy in retaliation for a clumsy aerial challenge.
"We have no problem in offensive areas but I have a big problem in midfield and at the back because Lauren, Parlour, Vieira, Gilberto and Keown are not available," Wenger said.
He has ruled out Brazil's Gilberto despite the limited options in midfield since the Brazilian returns from World Cup qualifying duty with his national team only 24 hours before Saturday's afternoon kickoff.
NO GILBERTO
"Gilberto will come back Friday afternoon and we have had bad experiences with players coming back (close to games)," Wenger told the club's official website.
Unbeaten Arsenal's position at the top is under threat from Chelsea, who are one point behind in second spot and play at Southampton on Saturday, and United who are a further point back in third place and face Blackburn Rovers at Old Trafford.
Wenger also has a decisive Champions League Group B match on Tuesday to think about as he weighs up his team selection for Saturday.
"We play on Tuesday night at Inter Milan so I don't think it will be a good situation for Saturday or the midweek game," he said.
Wenger said his options include playing 18-year-old Justin Hoyte at right back or moving Kolo Toure there with Pascal Cygan slotting in at centre back.
"But I don't know what I'll do in the middle either. I'll have to re-think the whole problem and at the moment I have not made a decision."
Birmingham manager Steve Bruce, in contrast, has a player in central defence that Wenger probably now wishes he had not released in the close season, England's Matthew Upson.
Bruce, whose side are a surprise fifth in the standings, will have to do without French forward Christophe Dugarry, who has not recovered from a knee injury suffered against Wolverhampton Wanderers two weeks ago.
But he has been boosted by the arrangement with Chelsea, announced on Thursday, for Finnish striker Mikael Forssell to stay at St Andrews on loan until the end of the season.
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