Mouse.position from center of player

Hey, Im working on a side scroller and the player rotates left or right depending on the position of the mouse in relation to the center of the screen. Heres the code;

var MousePosition = Input.mousePosition;
MousePosition.x -= Screen.width / 2;
MousePosition.y -= Screen.height / 2;
if(MousePosition.x < 0)
{
    transform.rotation = Quaternion.Euler(0,180,0);
}
else if(MousePosition.x > 0)
{
    transform.rotation = Quaternion.Euler(0,0,0);
}

Now what Id like to do is have the players position on screen (the camera has a Lerp smooth follow thing on it) offset were the rotation takes place, kind of like screen.width is local, if that makes sense.

You can get the players position on the screen using Camera.WorldToScreenPoint(). Once you have this you can easily compare it to your mouse position, hope this helps:

var MousePosition = Input.mousePosition;
var PlayerPosition = Camera.main.WorldToScreenPoint(transform.position);

if(MousePosition.x < PlayerPosition.x)
{
    transform.rotation = Quaternion.Euler(0,180,0);
}
else if(MousePosition.x > PlayerPosition.x)
{
    transform.rotation = Quaternion.Euler(0,0,0);
}