Freddie Woodman has refused to sign a new deal.
While Newcastle are desperate to keep the 22-year-old, the goalkeeper himself has been left frustrated by his lack of loan moves.
Premier League clubs are believed to be tracking the England Under-21 international and Newcastle's resolve may be tested if they receive a substantial offer for Woodman this summer.
With Benitez keen to have three senior goalkeepers in his Premier League squad at any given time, the United recruitment department have been identifying potential shot-stopper targets around Europe in case the Magpies lose anyone this summer.
But the takeover uncertainty, and the failure to reach a resolution regarding Benitez's contract, means it is still unclear whether United will look to sign another goalkeeper during the current window.