Newcastle United are reportedly chasing Eredivisie duo Erik Pieters and Douglas.
According to The Mirror, Brazilian centre-back Douglas could be on his way to Tyneside in a £6m summer deal from FC Twente.
Among those also leading the chase for the 24-year-old are Ajax and Schalke 04.
Meanwhile, PSV Einhoven left-back Pieters could strengthen Alan Pardew's backline for £5m.
Contract talks wth Danny Simpson are said to be at an impasse and the two defenders will act as cover for the Magpies.