Sunderland manager Paolo Di Canio has revealed that he sold Stephane Sessegnon because the winger had lost his desire to play for the club.
The Benin international, 29, joined Premier League rivals West Bromwich Albion for £5.5m during the summer transfer window.
Di Canio told the Sunderland Echo: "Always know this - that purely as a player, I wanted to keep him. But he did not make me enjoy the first three games in the league this season - he was a surprising negative in our performances.
"And then I said, okay, I think after three years, if a player is not showing the desire, if he is not homegrown or does not belong to this club, it is easy for a big player to lose his desire.
"So when they told me there was this chance for him to move, I decided we should take it. Best of luck to him."
Sessegnon arrived at the Stadium of Light from Paris Saint-Germain in 2011.