Charlton duo Patrick Bauer and Ahmed Kashi have been ruled out for up to a month with foot injuries.
Both players have been first-team regulars under Karl Robinson this season, but could now miss the whole of December.
Kashi’s injury is not a reoccurrence of an achilles problem that kept him sidelined for two years.
It’s a massive blow for Charlton, who have been decimated by injuries in recent weeks. Tariqe Fosu, Joe Dodoo and Lewis Page remain out.
However, Chris Solly, Billy Clarke and Ben Reeves are expected to return against Portsmouth on Saturday.
Jason Pearce and Harry Lennon, who played a half each in the Checkatrade Trophy win over Swansea U21s on Tuesday after recovering from long-term injuries, could be fit enough for the bench.
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