The Morocco youth international departs to join Real Madrid Castilla, while the Spanish giants have secured a purchase option worth €2m should the young forward's performances live up to expectations.
Granada's new deal ensures the club does not lose one of its brightest academy talents for nothing, with the option to extend the contract by a further two seasons.
With this arrangement, Granada avoid letting a prized asset go for free and secure his return to Los Cármenes if the loan spell in Madrid does not work out.
Zinebi, born in Barcelona to Moroccan parents, joined Granada from Catalan side AE Prat last summer and has progressed rapidly, scoring 16 goals in total between Tercera RFEF and youth football before making his first-team debut for the club this year.
This season was supposed to be Zinebi's chance to break through at senior level, but the emergence of Nigerian forward Chinaza Marvellous and the arrival of Venezuela international Alejandro Marqués blocked his path at Los Cármenes, prompting the move in search of regular minutes elsewhere.
Zinebi is currently on international duty with Morocco's Under-20s at the Mediterranean Games and will join up with Real Madrid Castilla once that commitment concludes.
The move continues a pattern this summer of Real Madrid dipping into Granada's academy, having already agreed a permanent deal for defender Óscar Naasei.
Zinebi will link up with Castilla, coached by Julián López de Lerma, as he looks to establish himself at one of the biggest academies in Europe, with Real Madrid C, led by Marc Carrasco, offering a further pathway if he needs additional time to adapt.
Granada's willingness to insist on a buyback safeguard reflects a summer in which the club has been keen to avoid repeating the loss of forward Samu, who left for Atlético Madrid by triggering his release clause shortly after impressing on his league debut.
By tying Zinebi to a longer contract before sanctioning the loan, Granada ensure they retain control of his future rather than risk losing him for a smaller fee down the line.