The striker has not suffered major damage, but he will be missing for 14 days after an MRI scan revealed the full extent of his problem
The striker was named in the squad to face Atletico Madrid on Sunday but withdrew on the morning of the game after jarring his knee in training.
And though there were initial fears that the problem could be more serious, an MRI scan has revealed the injury is only a minor one.
It has been an eventful couple of weeks for the 27-year-old, who agreed to join Juventus on a four-year-deal last Thursday, when his current contract at San Mames expires at the end of the season.
Llorente has been out of favour for large periods of the campaign after making clear his intention not to renew his contract with Athletic.
Coach Marcelo Bielsa has since opted to use the player sparingly and he has just two goals in 22 appearances to his name this season.