Ronaldo initially tested positive for the virus while on international duty with Portugal earlier this month.
The forward missed the last four games but is now able to return after testing negative.
Juventus' statement:
"Cristiano Ronaldo carried out a check with a diagnostic test (swab) for Covid 19.
"The exam provided a negative result. The player has, therefore, recovered after 19 days and is no longer subjected to home isolation.
The Italian champions travel to Spezia on Sunday afternoon, but it remains to be seen if Ronaldo will be a part of the squad.
1. Cristiano Ronaldo – 134 goals
10. Alfredo Di Stefano – 49 goals
9. Filippo Inzaghi – 50 goals
8. Thierry Henry – 51 goals
7. Andriy Shevchenko – 59 goals
6. Ruud van Nistelrooy – 60 goals
=4. Karim Benzema – 71 goals
3. Robert Lewandowski – 73 goals
=4. Raul Gonzalez – 71 goals
2. Lionel Messi – 119 goals
Scroll through the gallery to see the 10 leading goalscorers in UEFA Champions League / European Cup history