O'Brien was restored to the Rams' starting line-up against Burnley on Boxing Day after missing Friday night's home defeat to Hull after failing to recover from a bout of illness.
However, the 20-year-old went off seven minutes from the end of the 2-0 defeat at Turf Moor with a tight groin.
James O'Connor replaced O'Brien against the Tigers and he is likely to come back into the team should the academy product miss out again at The Valley.
Craig Bryson may be rested in south east London. The midfielder has been playing despite a knee problem and was replaced after 65 minutes on Boxing Day.
Depending on how manager Nigel Clough lines up his team against the Addicks, either Nathan Tyson, Theo Robinson, Conor Doyle, Ben Davies or Kieron Freeman could all replace Bryson should the Scot be given the afternoon off on Saturday.
- Sports & Recreation