"It is incredible that with this squad we have appeared to be fighting relegation," he told the Daily Mail.
"I must admit I don't really understand it and it has been the one question talked about more than any other in our dressing room.
"One theory I have is that the constant rumours about possible reinforcements in January have damaged us in some way.
"Some of my team-mates do perhaps fear for their future and that is not positive, I guess.
"But there is nothing we can do about that apart from try not to let it affect us."