More than just rumors, Koeman himself (Sep 22
https://www.theguardian.com/footbal...ules-out-oumar-niasse-rescuing-everton-career) said this:
Asked whether he was surprised by Niasse’s stance, having been in no doubt he would not feature this season, Koeman replied: “That’s a question for the player.
There was some interest in him but not the interest that he liked to have. It is all up to the player whether he doesn’t leave, I can’t understand it but that is normal. Football players like to play football, that’s how I see it, and I explained to him why he was not in my plans for the season.”
As for being good enough for another premier league club but not for us there are any number of reasons why that could be so. First of all, he was going out on loan so there is a financial aspect of affordability with respect to filling a squad place. Secondly, other teams/scouts/managers may determine that Oumar would be useful to their squad and suits their style of play. Thirdly, our standards and ambitions are higher than those teams who came in for him.
I think it is more than him being just crap, I think he is an actual danger to other players in training. He already injured someone in training for us last year with a bad tackle. Other clubs might not be aware of the extent of just how bad a player he is and are willing to take the gamble.