Wenger acknowledged it has been a blow to lose two of his most influential players but he is concentrating his mind on those currently at the Club.
"The summer was difficult because we had Fabregas and Nasri on permanent transfer negotiations and that is draining in the end," the manager told arsenal.com.
"We lost two great players and that's the sad side of the story but at some stage it has to be over because we want to focus on the future.
"Overall what you do not want is to have players who play and think they go the next morning, that is not ideal. You want players who are completely committed to the long term, to defend our chances."
Wenger would prefer to have resolved the futures of Fabregas and Nasri earlier than August but he explained that the timing was out of his control.
"It is not naive [to think it could have happened sooner] but what you forget is that it does not depend only on us," he said.
"We wanted to sort all these cases out very early after the summer but it wasn't possible and the pace is not only dictated by us unfortunately."