Defender Peltier and Austin have both had scans on respective ankle injuries and Tonge is still struggling with the shoulder injury he sustained in the recent win over Barnsley.
Austin is the least likely to make it in time, but fellow midfielders David Norris (thigh) and Paul Green (knee) returned to the starting line-up on Tuesday night following long injury lay-offs and provide manager Neil Warnock with several midfield options.
Warnock recalled defender Adam Drury and forward Luke Varney to his starting line-up against Charlton at the expense of Aidy White and Tonge, and must decide whether to retain them.
Recent loan signing Ryan Hall has been an unused substitute in Leeds' last two matches following his arrival from Southend and is pushing for his debut, but striker Ross McCormack (ankle) is still out.
Leeds are unbeaten since mid-September with three wins and three draws from their last six league games.
Birmingham's Jonathan Spector hopes to return for the trip to Leeds.
The midfielder missed Tuesday's dramatic 3-3 draw at Millwall through suspension having been sent off against Leicester last weekend, during which he also suffered a thigh problem.
Spector is now free of suspension and has also overcome the injury, with the American returning to training with his team-mates on Friday ahead of the Elland Road encounter.
Nikola Zigic, who scored four times in a 4-1 win in the corresponding fixture last season, serves the final game of his three-match ban and misses out.
Peter Lovenkrands (groin) and Pablo Ibanez (broken toe) are also sidelined, although the pair have stepped up their respective recoveries and should return next week.
Full-backs Stephen Carr (knee) and Paul Caddis (shoulder) continue to miss out with their long-term injuries.