Estupinan missed the most recent international friendly due to a knee sprain, Ecuador announced.
Analysis:Estupinan will take further tests upon returning to Milan, and the early indication is that the problem is minor, Gianluca Di Marzio reports, although it remains to be seen whether he'll be able to recover for Sunday's away game versus Sassuolo. Davide Bartesaghi and Diego Moreira are the other options in the role.
