But the 28-year-old is staying in Spain for now, after signing for Malaga on loan from Villarreal.
Wolves brought in Joao Moutinho and Leander Dendoncker to fill the void left by N'Diaye, with Cardiff eventually turning to Victor Camarasa and Harry Arter instead.
And although Middlesbrough's failed to add in N'Diaye's position, the Teessiders have until August 31st to rectify that in the window for standard loans.
Malaga finished bottom of La Liga this season, ending their decade-long stay in the top flight.
Will Cardiff/Midddlesbrough/Wolves regret not signing N'Diaye?