Viana, 23, joined Newcastle for £7 million three years ago and has completed a move to Valencia in Spain for £2 million.
The midfielder, a substitute for Portugal in the 1-0 win over Angola on Sunday, was signed by Sir Bobby Robson from Sporting Lisbon but spent a loan spell at his former club before joining the Spaniards last season in a similar deal.
He never settled on Tyneside and struggled in the Premiership, insisting (like so many Latin players who come to Newcastle) that it was "too physical" for him.
More money thrown down the drain, as the list of Latin failures continues: Marcelino, Guivarc'h, Bassedas, Cordone, Gavillan, etc. And don't hold your breath waiting for Luque to turn the tide, because reports this week suggest he has played his last game in the Premiership.