However, West Ham's offer for the Mexican striker will remain on the table as they hope United's stance will soften as they look set to make further inroads in the transfer market.
With Robin van Persie departed, Hernandez is one of few forwards left in the Old Trafford stable, but still West Ham hope to prise him away and they believe they are in pole position to capture him.
However, HITC Sport has been told that United have given West Ham a straight answer after they launched a bid for his signature earlier this week after first making contact at the start of the month.
A source has told HITC Sport: "United have said no, and that is where the situation is - West Ham are going to wait, but clearly they cannot wait forever, but Slaven Bilic does really like him."
One player who won't be arriving at West Ham is Mattia Destro. HITC Sport has been told that West Ham did show an interest after being offered the Italian international - but they will not be making a firm offer.