Newcastle have missed out on the signing of Nico Schlotterbeck, 90min understands, with Borussia Dortmund set to complete a deal for the 22-year-old.
Schlotterbeck was one of a number of centre-backs targeted by Newcastle in the January transfer window, but the German opted against rushing into a move so that he could consider all of his options.
Newcastle had continued to monitor Schlotterbeck - who earned his first international caps for Germany this year - in the hope of resurrecting a deal this summer, but 90min can confirm reports that he has decided to join Borussia Dortmund - where he will link up with Bayern Munch defender Niklas Sule, who is out of contract this summer and has already agreed a move.
Schlotterbeck's decision comes just two weeks after Lille defender Sven Botman, another player Newcastle were extremely keen to land, agreed terms with AC Milan.
Nevertheless, Newcastle expect to sign at least one new centre-back once the summer transfer window opens, and sources have told 90min that Newcastle manager Eddie Howe will likely operate with a budget of around £100m.
Indeed, Howe recently admitted that Newcastle wouldn't be able to fund a complete overhaul of their squad, and would instead have to deal with 'financial restrictions'.
Sevilla defender Diego Carlos remains a target for Newcastle, despite a January move falling by the wayside, while Howe could also turn to Bournemouth's Lloyd Kelly - a player he is more than familiar with having signed him during his lengthy tenure on the south coast.
The 23-year-old appears destined to play in the Premier League as Bournemouth are closing in on promotion, but the chance to move to St James' Park to reunite with Howe could prove difficult to turn down.