Sels has spent the whole of the campaign on loan with the Belgian side, and they are keen to snap him up.
However, Anderlecht have seen their first offer rejected by Rafael Benitez’s side.
Anderlecht have reportedly offered £1.75 million to Newcastle for the 26-year-old, but the Magpies want at least £500,000 more.
The Magpies are refusing to let Sels go on the cheap, which now puts the transfer into serious doubt.
The Sun claim that Newcastle could now be left with four senior goalkeepers on their books heading into next season.
Newcastle already have Karl Darlow, Martin Dubravka and Rob Elliott at the club, and it seems unlikely that Sels has any future with Benitez’s side.