Phaser duda basica problema cargar imagen

Acabo de empezar a utilizar phaser.

Y me tira todo el rato este error Phaser.Cache.getImage: Key "player" not found in Cache.

var mainState = {
      preaload: function()  {
      game.load.image('player', 'assets/player.png');        

    },
    

create: function()  {
    game.stage.backgroundColor = '#3498db';
    game.physics.startSystem(Phaser.Physics.ARCADE);
    
    var player = game.add.sprite(250, 170, 'player');

},

update: function()  {
    
},


   


};

var game = new Phaser.Game(500, 340, Phaser.AUTO, 'gameDiv');
   

game.state.add('main', mainState);
game.state.start('main');