Zanetti's career was called into question in April after the veteran ruptured his Achilles tendon, but the Argentine recovered and came off the bench to end a seven-month spell on the sidelines in a 2-0 win at the San Siro on Saturday.
The 40-year-old has revealed that Chelsea manager Jose Mourinho was among the well-wishers ahead of his comeback, before declaring that he is ready to help Walter Mazzarri's team in any way he can this season.
He told reporters: "It was very emotional, as after the operation I had promised to return for at least one game in front of my fans. I could not have asked for more.
"I haven't been able to read all the messages I received yet, but I also got one from London (Mourinho). I am just happy to be back and an extra alternative for the team.
"Right now the side is doing very well, I need to find my form, so I can be an alternative off the bench to make myself useful in any role I'm needed. There's no problem there."
The Nerrazzurri are currently fourth in the Serie A standings after winning seven of their first 12 games under Mazzarri's guidance.