Sources at the club were quoted as saying "not everyone fits" when asked about the implications of the deal, given an attack that already includes Kylian Mbappé, Jude Bellingham, Vinícius, Diomande, Franco Mastantuono, Brahim Díaz, Gonzalo García and Endrick, with Rodrygo also still on the books despite a long-term injury.
Real Madrid have already ruled out both Federico Valverde and Bellingham as candidates to depart, with Valverde set to be named captain and Bellingham considered undroppable after his outstanding World Cup with England.
That leaves Vinícius as the name club officials most want to move on, though the situation remains complicated by his contract status. The Brazilian is seeking a significant pay rise as he enters the final year of his deal, with reports suggesting he wants close to €30 million net per season to match the wages of team-mate Mbappé. Real Madrid have long maintained that if Vinícius failed to renew before the World Cup, as has now happened, the club would look to sell rather than risk losing him for nothing next summer.
Arsenal's interest, which emerged in recent days, is so far the only concrete interest in Vinícius, with no other club having approached Real Madrid about the 26-year-old. A deal will not be straightforward given his standing at the club and his importance to Jose Mourinho's attack, but sources close to the situation say his departure remains the leading candidate to become the defining exit of Real Madrid's summer following the arrival of Diomande, who shares the same representation agency, Roc Nation, as Vinícius himself.
The Diomande signing is seen internally as reinforcement for the left flank regardless of how the Vinícius situation resolves, given the Ivorian's ability to operate on either wing. Should Vinícius ultimately stay, Real Madrid would still be left with a considerable overload of attacking options, adding further weight to the argument for a departure elsewhere in the front line even if it is not Vinícius who leaves.
For now, all indications from within the club point towards the Brazilian as the player whose future carries the greatest uncertainty as the transfer window enters its final stretch.