It is impossible for Luis Suarez to return to Barcelona because the basis of Suarez's sale to Atletico Madrid is because he is no longer young and Barcelona needs younger players because of Barca's busy schedule. I think you still remember the reason why Barcelona officials let Luis Suarez off a few years ago.
Suarez and Messi were in very good form in Barcelona. However, the Barcelona management did not extend the contract with them because they are now looking for young talent. Xavi is not interested at this moment on Messi or Suarez. He is now keen to invest on young players. However, Barcelona is now keen to sign Lewandowski, as they now need an experienced striker to win next season's title.