Ronald Koeman has had some conflicts with players recently. The last one was with Riqui Puig, that is still ongoing. He accused him of leaking inside information to the press and tried to get rid of him. And at the beginning of the season, he kicked out Luis Suarez of FC Barcelona in a phone call.
Now, a player he managed some years ago came out and talked about the time he became a target for Koeman's anger. When the Dutch was appointed in the club he was playing for, he was kicked out on loan and when he came back and a permanent transfer fell through, he was immediatly isolated.
That player is Oumar Niasse, who suffered Koeman in 2017, at Everton. The coach took his shirt number and his locker in the dressing room and gave them to a young player. He even kicked him out of the dining room, sending him with the U-23 players. Niasse was 27 at the time.
The Senegalese told he noticed that Koeman was making all that effort to make him lash out in anger, and kick him out with an excuse to say he was conflictive. Curiously, Niasse outlasted Koeman, sacked in October 2017. But he suffered that period where he had to stay mentally strong to deal with not being respected at all. Probably, a couple of FC Barcelona players can see what he is talking about.