The player is to join Eskisehirspor on a season-long loan, despite having only arrived from another Turkish side, Bursaspor, in a £3.8m deal in January.
"There was no problem with the coach," N'Diaye told the Sunderland Echo.
"We talked about my expectations because I need playing time. I'm at an age
where I need to play, so it was agreed to my loan and I chose Turkey.
"After the half-season I spent at Sunderland, starting on the bench was not
what I wanted.
"I am only 23, but you must play every week to progress. I could have stayed
at Sunderland, but I preferred the loan."
The move sees N'Diaye reunited with his former coach at Bursaspor, Ertugrul
Saglam, who is now in charge at Eskisehirspor.
N'Diaye, who made 15 league starts for Sunderland, added: "I had several offers, but it is this one in Turkey that gave me the most motivation.
"I know the coach, I spoke with him and he is counting on me for the upcoming season. This offer guaranteed me the most playing time."