Daryl Janmaat will undergo a medical at Watford after Newcastle accepted a £7.5million bid for the full-back.
The Holland international has made two appearances in the Championship for the Magpies the season, in the defeats to Fulham and Huddersfield.
Janmaat joined Newcastle in a £5million move from Feyenoord two years ago.
And Rafa Benitez is set to replace the 27-year-old with Tottenham’s right-back DeAndre Yedlin, who spent last season on loan at Sunderland.
Yedlin, 23, arrived in Newcastle on Tuesday ahead of a £5million move from St James’ Park.