Sunderland have made an enquiry to sign Valencia's Argentina midfielder Ever Banega, according to Sky sources.
The 25-year-old has 24 senior caps for his country and signing Banega would represent something of a coup for Poyet.
Banega would become the third Argentinian to head for Wearside this month, with goalkeeper Oscar Ustari and central defender Santiago Vergini - who could make their debut in Saturday's FA Cup fourth-round tie against Kidderminster - already signed.
Poyet has also signed Spanish full-back Marcos Alonso on loan from Fiorentina.
Poyet is believed to be keen on signing Liam Bridcutt from his former club Brighton.
As far as prospective signings are concerned, Sunderland are a more attractive proposition now than they did at the start of the transfer window, having reached the final of the Capital One Cup in midweek.