Jason Van Blerk - soon to be suspended
The 33-year-old Aussie was shown a second yellow card for arguing with the referee after Rushden were awarded a penalty - just seven minutes after scoring his first goal in black and amber.
He will miss the games at Rochdale and Swansea City next week. Andy Holt is expected to take his place at left-back.
Van Blerk has seen red twice this season, after being dismissed in his last game for Stockport.