The 26-year-old Niasse, who has been forced to train with Everton's under-23 squad, is yet to feature for the Merseyside club this campaign and has made just two starts since his 13.5 million pound ($16.79 million) arrival in January.
"I want to show myself in the Premier League and I hope it can be at Everton, because it's the team that I'm feeling. Every weekend, I'm watching the games, I'm supporting the team, I'm behind them. I'm a blue," Niasse told the Guardian.
Media reports suggested the Senegal international had offers from clubs in Germany, Spain, Portugal and Turkey but turned them down as he hoped to succeed in England's top flight.
"But, if I get the opportunity to show what I can do at another Premier League team, I will go and I will do it. You never know what can happen. This is football," he added.
"Koeman said: 'You have to leave'. I couldn't understand how that decision could have been made after 45 minutes but I just said: 'OK, thank you'. It's his decision. He's the manager. What can I do?"
Fifth-placed Everton travel to leaders Manchester City for a Premier League encounter on Saturday.
