The 29-year-old played his first match in more than 18 months last night in a 4-1 friendly win over Peruvian side Bolivar.
Milito has been out of action since damaging his anterior cruciate ligaments in the 2007/08 Champions League semi-final against Manchester United.
“I had a very good feeling after such a long time out,” he told Barca TV.
“I am making very significant progress even though I know I am still locked in the recovery phase.
“I don’t know (when I will play a competitive match) but it’ll take a while yet.”