Reports suggest Aleksandar Mitrovic - who joined the Cottagers on a permanent deal for £22m last season - might leave in the summer.
He left the pitch a sad figure on Sunday, surpised at the mocking he took from the Toon Army.
Once the hero, his comments that Fulham supporters were "better than the Geordies" didn't fall on deaf ears.
Another former Newcastle player, Scott Parker,was equally as shocked as his centre forward during the final stages of the match.
The former assistant was handed the top job permanently this week and with it the task of reinvigorating an expensively-assembled outfit that many expected to do well, but in the end failed to meet acceptable standards.
He said after his appointment that "success comes from a foundation, that foundation comes from a culture and setting standards on a daily basis".
In the first few minutes of the match, his side set high standards as they tested the visiting defence with balls flung in from both wings - Aleksandar Mitrovic went close with a header that drifted a foot wide of Martin Dubravka's post.
The ex-Newcastle striker also had a chance with another header that should have found the target but aside from that, and a good strike by 16-year-old substitute Harvey Elliott, the Slovak keeper had a fairly quiet day at the office.
It has been their defence which has been been Fulham's Achilles heel. Every time Newcastle attacked, they looked liable to concede. Rondon's late strike was the 81st conceded in the league this season - five more than bottom club Huddersfield.
Top of Parker's summer shopping list must be a new backline.