Allardyce said: "Everybody knows what happened against Portsmouth last month, but what I have to say is that everybody can have an off-day.
"Claudio made a couple of mistakes in the space of five minutes, and that's why I brought him off.
"He was not 100 per cent fit, but he wanted to play, and looking back, perhaps that was not the best decision he has made.
"But before Portsmouth, I also have to say that Claudio had been superb for us, and we have missed his experience and his guile.
"It's too early to start to talk about our team for Fulham, but we have to stop conceding silly goals."