Paz suffered a heavy blow to the knee during Como's match against Hellas Verona last week and has been unable to train normally since. He can walk without difficulty and perform light rehabilitation exercises, but pain increases significantly under competitive load or high-intensity movement — precisely the concern that prompted Argentina's medical staff to act.
Initial scans carried out in Italy have not confirmed serious structural damage, but a definitive diagnosis has not yet been reached. Argentina's medical team reviewed those tests and were not fully satisfied with the picture they presented, leading to the decision to send their own doctor to make an independent assessment.
Como head coach Cesc Fàbregas, speaking to reporters on Sunday, acknowledged the uncertainty surrounding his availability for the final round of Serie A fixtures, which carry enormous significance for the club. Como are fighting for a Champions League place and face Cremonese on the final day.
"I don't know if he will be available for the last game. I hope so, but I cannot guarantee it."
Paz has had a standout season, contributing 12 goals and seven assists in 35 league appearances. Real Madrid hold a buy-back option on the player, who joined Como from the Spanish club last summer. He features among the near-certainties in Lionel Scaloni's provisional 55-man World Cup squad, and is expected to make the final 26-man list before the May 30 submission deadline.
Argentina open their World Cup campaign against Algeria on June 16 as defending champions. The tournament begins on June 11.