It is a familiar position for the 19-year-old Brazilian, who struggled for opportunities under Carlo Ancelotti two seasons ago and again last season under Xabi Alonso before eventually joining Olympique Lyon on loan in January - a move that nevertheless opened the door to a place in Brazil's World Cup squad.
At the Club World Cup before that loan, his path forward had already been blocked by the emergence of Gonzalo García, though Endrick still finished as top scorer in that season's Copa del Rey under Ancelotti.
Gonzalo's sale to Fulham this summer might have been expected to ease the logjam, but Real Madrid moved quickly in the market to sign Carlos Espí as a out-and-out centre-forward, a clear signal from both the club and Mourinho - who gave his approval for the new striker's arrival - that Endrick cannot simply expect to inherit the No.9 shirt.
The Brazilian could still look for space out wide on the right, though even that route looks increasingly narrow following Real's move to sign Yan Diomande.
Even so, Endrick's situation will not be resolved within days. He wants to keep playing through pre-season and believes he can still win Mourinho over, having cut short his holiday to report for training as early as possible because he felt there was no time to waste.
He started Real's friendly against Fiorentina having barely trained with the squad, and duly got on the scoresheet; Mourinho has also been seen praising him out loud during training sessions after good moments in play.
Unlike last year, Endrick had not been contemplating a second loan exit this summer - his plan was to return and force his way into Mourinho's side.
But competition remains fierce, and the only route that would meaningfully open up space for him at the top of the pitch, however unlikely, would be a departure of size from the front line - namely Vinicius Jr, whose future at the club looks more secure than ever after this week's contract extension.