GetComponent returns null

Hi all,

I am receiving null when I perform a GetComponent(). I saw that this problem is quite frequently asked on this forum, in these cases the problem is mostly caused by: - The script not being attached to the gameobject - The instance variable not being initialized

I don't think this is the cause here though - or I am missing something. As following my code (note that I am new to Unity). In the console log I can see the following output:

 Start
  PlayerBall is null
  End

Meaning the LineRenderer linked to the gameobject can be resolved, but the Player object can not.

Player class:

 public class Cue : MonoBehaviour {
     public GameController game;
     public LineRenderer line;
     public Player playerBall;
 
     Cue()
     {
 
     }
     void Start () {
         Debug.Log("Start");
         line = GetComponent<Cue>().line;
         if (line == null)
         {
             Debug.Log("Line is null");
         }
         playerBall = GetComponent<Player>();
         if (playerBall == null)
         {
             Debug.Log("PlayerBall is null");
         }
         Debug.Log("End");
     }
 
     // Update is called once per frame
     void FixedUpdate()
     {
         /* do stuff */
     }
 
     void OnMouseDown()
     {
         
     }
 }

In Unity, the following properties are set:

The Player object:

 public class Player : MonoBehaviour
 {
     private int count;
     public Text UIScore;
     public Rigidbody rb;
 
     protected void Start()
     {
         rb = GetComponent<Rigidbody>();
         count = 0;
         updateScore();
     }
     void FixedUpdate()
     {
         /* do stuff*/
     }
 
     void OnMouseDown()
     {
     /* do stuff */
     }
 
     void OnCollisionEnter(Collision collision)
     {
         if (collision.gameObject.CompareTag("Ball"))
         {
             count++;
         }
         updateScore();
     }
 
     void updateScore()
     {
         UIScore.text = "Player ball Collision count: " + count.ToString();
     }
 }