Rizwan and Irfan both suffered hamstring injuries in the third match in Rawalpindi
Real said tests were conducted on the squad on Monday and that though Diaz was in "perfect health", he would be self-isolating at home.
Real, who trail Manchester City 2-1 from the first leg of their last-16 tie before the pandemic suspended the competition in March, are set to play the Premier League side in the second leg on Aug. 8 at the Etihad.