Town secured their first point of the season thanks to a 1-1 draw with promotion favourites QPR without former Watford midfielder Hogg, who fell ill on the eve of the match.
"I found out at 12.30pm, which messed up my plans a little," manager Mark Robins told reporters. "It changed the dynamic, especially as Oscar (Gobern) missed the midweek game with a hip injury.
"He did his job very well though and helped us get a point. Hopefully Jonathan will clear his illness and be back for next Saturday."
Robins was satisfied with his side's display, but feels there is room for improvement. "I am happy that we have got a point from our opening week," he added.
"It could have been more. We could have got a draw at Forest and won against QPR.
"We stuck to our task well, but I would still like to see us be more positive in attack. We tried to implement our passing game, but it was difficult. We will keep trying, though, and we will get better."