In my opinion, it does not matter how much Adriano's condition improves or how many goals he scores for Sao Paulo. I believe these considerations count for very little when you take into consideration the breakdown of the relationship between Adriano and Mancini.
We all know how stubborn Mancini is. Adriano may return to being one of the world's most feared strikers but Mancini will not back down and it is for that reason I fear Adriano's return to Milan. There is every chance, even if his form warrants a starting place alongside Zlatan, that Mancini will simply disregard and leave Adriano in the stands. If such were to happen, Adriano will be a broken player and the rehabilitation and 6 month loan spell in Brazil will count for nothing.
That is why I believe all the talk of weight loss and improved condition counts for very little and even if Adriano starts reasserting himself on the pitch, the fact remains that Adriano is unhappy at the way Mancini has treated him and Mancini claims to either not know what is happening with Adriano or voices a wait and see approach.
Essentially, what I am trying to say is that as long as Mancini is Inter coach, Adriano, regardless of form, will be a periphery figure. The relationship between player and coach has broken down and they appear to have ireconciliable differences.
Best of luck Adri! We will be keeping a very close on eye you.