The Turkey international sustained the damage late on in Tuesday's 3-2 win over Porto, which cpuld not prevent Juve exiting the Champions League on away goals at the last 16 stage.
Juve confirmed on Thursday that Demiral, who has been plagued by a number of injury setbacks over the past year, suffered low-grade tissue damage.
He is expected to miss 20 days, potentially ruling the 23-year-old out of Juventus' Serie A games with Cagliari, Napoli and Benevento.
Demiral is subsequently a major doubt for Turkey's World Cup qualifying triple-header against the Netherlands, Norway and Latvia later this month.
