I don't know if it's possible to leave Barcelona now, but most likely not. The situation is as funny and incomprehensible as possible. Funny because Sergio came for Messi's sake, and Messi left the club. It seems like lawyers and a football agent are trying to solve the issue of leaving the club due to non-fulfilment of conditions (related to Messi), but even if it works, where will it go? It's unlikely to be accepted back in MC, other top clubs have already bought players for the start of the season. The option is only to wait for next year to make the transition
Thats the big mistake from Aguero's end due to his strong friendship with Messi and I believe this is one of the reasons he's having a problem of making it to the club top 11 players. He ought to have to go to Arsenal or Chelsea which shows strong interest in him but it what it is.
Yes, of course. After he probably wanted to leave the team as soon as he joined it, Sergio's credibility would simply disappear. Even in the last match, he wasn't released on the field, that already tells us something. Who knows if he can really leave the team already in this transfer window? It's unlikely, but still