Create:
        playergroup = this.add.group();
        playergroup.enableBody = true;
        playergroup.physicsBodyType = Phaser.Physics.ARCADE;
        playergroup.setAll('checkWorldBounds', true);
        playergroup.setAll('outOfBoundsKill', true);
        playergroup.setAll('anchor.x', 0.5);
        playergroup.setAll('anchor.y', 0.5);

    /*...*/

        player = this.add.sprite(this.world.centerX, this.world.centerY, 'green');
        player.anchor.set(0.5);

    /*...*/

    orbiter = this.add.sprite(0, 0, 'red', 0, playergroup);
        orbiter.pivot.x = -40;
        orbiter.pivot.y = 0;

        playergroup.x = player.body.x;
        playergroup.y = player.body.y;

Update:
        orbiter.angle += 1;