The Argentine has been missing for a month.
Milito said: "I am disappointed to be out and not being able to give my contribution.
"I will have a scan in the next few days. I am working well. But I still need a week. I must be completely fine so I don't get injured anymore.
"At this level when you play a lot, you must be at your best."
When asked for his reaction to Samuel Eto'o thriving in his absence, Milito said: "I have a great relationship with him.
"We are very happy together on the pitch. We have shown it many times. He is doing great.
"I am very happy for him."