They are winless in 10 matches and have not scored in seven of those.
Lying second bottom they are also battling a player shortage, with Jake Livermore's fifth yellow card ruling him out of the Boxing Day trip to Sunderland and defenders Curtis Davies and Alex Bruce limping off.
"Today just highlighted for me the need for your big players," he said.
"I still expect a better performance than we witnessed in the second half but we're crying out for some of our bigger players. Whether it's injuries or suspensions we couldn't cope without them.
"You need your big established Premier League players and far too many of ours are sitting in the stands."