The report claims Fuentes hopes to secure a contract with Forest, who allowed Armand Traore to leave for Cardiff City last week.
It adds, however, that the Reds - whose manager Aitor Karanka is also Spanish - want to assess his overall fitness before committing to a deal.
Fuentes has made 84 appearances in Spain's top flight for Espanyol and Osasuna, who released him last summer.
Before joining Espanyol, the 28-year-old was on Cordoba's books - the same club from which Nottingham Forest signed another Spanish left-back, Dani Pinillos, who is now a Barnsley player.
Another deal in doubt?
Forest have also been linked with moves for Stefanos Kapino, a Greek international goalkeeper, and Javier Garrdio, the former Manchester City left-back - both of whom are available on free transfers.
The latter deal would surely be in doubt, however, should the Reds pursue their interest in Fuentes any further.
Would Fuentes be a good signing for Nottingham Forest?