Alex out for up to eight weeks
Alex has pulled out of Brazil's squad to play Argentina this week and is poised to have surgery, the champions added on their official website.
Chelsea's England defender John Terry missed the club's shock 3-0 home defeat by Sunderland on Sunday and could also be ruled out for months with a nerve problem in his leg.
"It has been manageable up until the last two weeks but it is at a point where I can't carry on with it," Terry was quoted as saying by British media.
"I used to be able to make it through games because the adrenaline gets going and you blank the pain out, but now there really is no decision to make," he added.
"After games I am in agony and not sleeping at all. I used to play with pain at seven out of 10. Now? It's 10 out of 10. I need to take a few weeks rest, see a couple of specialists and solve the problem."