Reports have suggested that the Tricolor are interested in taking the 29-year-old full-back on loan until the end of the year.
"Andre Santos depends on being released by his club," Gremio president Fabio Koff told Radio Guaiba.
"It's a negotiation that advanced, then moved backwards. Let's say we are interested and we had this well underway in advance."
Santos has also been linked with a move to Turkish champions Galatasaray.