Alves, who cost the club £12.7million in January 2008, still has three years remaining on his contract and it would take a sizeable bid before the Teessiders could even consider doing business, something which is perhaps unlikely with his form to date disappointing.
Alves has scored 13 goals in 47 league and cup appearances since joining Boro from Heerenveen in a £12million deal in January 2008.