The Nerazzurri are spending the November international break in 17th place having won just two of their opening nine Serie A matches.
“At this time, the difference between the reserves and the first team is too much, that is what the problem is," said Sneijder.
“We are the team with the highest average age to have ever played in the Champions League.
“But I am confident that if a couple of teammates come back then our form will improve. Nevertheless, I am very happy, the team can improve.”