Sergio Aguero has undergone stem cell surgery on his knees in order to try to regenerate the cartilage and prolong his career at the top level, Cadena SER's reliable Santi Ovalle reports.
It's said that the procedure was planned even before his Barcelona move was announced.
Top athletes like Pau Gasol (basketball), Rafa Nadal (tennis) and Carles Puyol underwent similar surgeries in the past.
Aguero seems to have a chronic knee problem. Last term, he missed a big chunk of the season through injury and ended up playing just 20 matches for Manchester City.
The Argentine is expected to join the pre-season at Barca in the first week of August.