Doncaster's appeal against Harry Forrester's red card picked up in the 3-1 defeat by Port Vale on Saturday has been unsuccessful.
Forrester saw red in the 79th minute after accidentally kicking Sam Johnson in the face as he lined up a shot after rounding the Vale goalkeeper, but the FA have upheld his three-game ban, meaning the ex- Aston Villa striker will not be available until the clash with Oldham on August 30.
"We are really surprised and really disappointed about this," admitted Dickov. "We felt we had a very, very good case put forward and we took a lot of advice from a lot of people in the game, including people within the referees and to get knocked back was really disappointing.
"But we have got to accept it and move on."