Gremio have approached Arsenal about signing Andre Santos - but face a race against time to land him.
The hapless left-back has been criticised by Arsenal fans this season for a series of error-strewn displays.
And Arsene Wenger appears to have lost faith in him, having signed Nacho Monreal in the transfer window.
Brazilian clubs have until Tuesday to register players for this season's Copa Libertadores and Gremio want Santos.
"Andre Santos is one of our interests. We talked with Arsenal, but there is nothing certain. It is a very difficult negotiation," President Fabio Koff told Brazilian newspaper Zero Hora.