The Elland Road outfit worked hard to sign Dieng from Marseille on deadline day this summer, with owner Andrea Radrizzani even going as far as to suggest the deal was done.
Dieng though had second thoughts about joining Leeds and snubbed the Whites in favour of a move to Nice, which then collapsed due to a failed medical.
Leeds did sign a forward player in the shape of Willy Gnonto, but the teenager is considered to be one for the future.
With Dieng still at Marseille, Leeds could go back in for him when the window opens again in January.
However, that looks unlikely, with Leeds not in touch with the striker’s representatives about a new year switch to Elland Road.
The Whites look set to hunt elsewhere for reinforcements when the window is open again.
While Dieng looks set to be someone Leeds will not revisit, they are tipped to try again for PSV Eindhoven winger Cody Gakpo.
