Forster, who should have been a certainty to start against the Rams, may struggle to force his way into the team even if he does declare himself fit after an electric performance from Jamie Cureton in last night's game against West Ham.
Alan Pardew told readingfc.co.uk the bad news: "It looks like Fozzy is a doubt for Saturday. He's missed three or four days of training and at this time of year thats not good. Its certainly a doubt as to whether he will be able to start at Pride Park."
Due to his illness Forster missed last nights game against the Hammers, whilst there was no ovbious signs that the team missed him hsi contribution is likely to be vital this season if Reading are to make an impact on Division One.
Fozzy has had a magnificent pre-season scoring five goals in five games.