Niasse revealed the shocking way the Dutchman treated him on Merseyside.
“When Koeman arrived I was a real good target to destroy,” Niasse told BBC.
“He tried, but I was strong enough to stay. I worked so hard to come to the Premier League so I had to stay in the Premier League. “For him (Koeman), he worked so hard to let me go. He tried to do a lot of things that were not nice.
“Having taken my locker, my shirt number, he took me out of the dining room where we eat and took me to the Under-23s without no locker there.
“It was very difficult. You need a very strong mindset to deal with that because you don’t have any respect at the club.
“Using the word ‘slavery’ is too much, but it was very difficult. That’s all I can say.”
While we know about Koeman, he's had 3 seasons since and couldn't get going, so that says a lot too.