The Colombian international has been linked with a host of clubs this week but it now appears that Juve has won the race for his signature.
"It seems certain at this point Fredy Guarin will be a Juventus player and today the news will be confirmed," agent Marcelo Ferreyra told O Jogo.
"To reach the agreement both Porto and Juventus had to compromise.
"The Portuguese club will get €11million and not €13m as they wanted, even if the amount goes up if he scores some goals."
The 25-year-old could seal his switch as early as this evening.