The 32-year-old Argentine, who joined City from Atletico Madrid over the summer, made his debut during Sunday's defeat at Chelsea following a spell on the sidelines with a knee injury.
"I have a lot of ambition, and have not come here to take a secondary role," he told the Manchester Evening News. "I want to be part of the team and am confident I will do it.
"The knee feels really good and I feel I am fit and ready to play at Newcastle [United], but it is the decision of the manager."
City travel to Newcastle in the fourth round of the Capital One Cup on Wednesday.