detectCollision - why do I need to check for object == NULL before strcmp?

strcmp

GObject object = detectCollision(window, ball);
if (object == paddle)
{
  //**this if works fine without checking for object == NULL***
  ydisp = -ydisp;
}

if (object == NULL)
{
  //***Why do I need to check if object == NULL in order for te next if (strcmp) to work? ***
}
else if
{strcmp(getType(object), "GRect") ==0)
{
  if (object != paddle)
    {
      ydisp = -ydisp;
      removeGWindow(window, object);
      etc
      etc
}    }