Having trouble getting started, specifically add.sprite issues

[zlegacy]

Hey all, I have a rather large codebase that I was hoping to convert to take advantage of Phaser and running into an issue that I am fairly clueless on.  I have loaded a sprite sheet and am trying to add the sprite to a player object but am getting this error: Uncaught TypeError: Cannot read property 'sprite' of undefined.

playerObject.prototype.createPlayer = function() {

    if (this.isDead == false) {

        // x, y, name

        let player_x = Array.isArray(room.map.json.player) ? room.map.json.player[0] : 0

        let player_y = Array.isArray(room.map.json.player) ? room.map.json.player[1] : 0

        this.physic = new physicsBody({

            type: "dynamic"

            , shape: "circle"

            , x: player_x / physics.scale

            , y: player_y / physics.scale

            , radius: 0.5

            , fixedRotation: true

            , mass: 20

            , userData: this

        })

        this.anim = mainGame.add.sprite(player_x, player_y, 'run')

    }

This is a multiplayer game, so I create all my players and am trying to assign this specific sprite.  I can console.log mainGame and get the proper information, so I know that's not undefined.  I'm not getting any other errors, so I'm really not sure what the problem is here.