Agent Chris Page confirmed to PA Sport: "We will be assessing Boro's interest now that Leeds have told us we can talk to them."
Boro boss Steve McClaren, though, may lose out again, for there is strong interest for the 28-year-old from several other clubs abroad, including Roma and maybe Benfica.
It remains to be seen whether Valencia will continue their interest, following the resignation yesterday of coach Rafael Benitez.