add_field_to_paneliser.php

<?php
$panelizer_nodes = db_select('node', 'n');
$panelizer_nodes->leftjoin('panelizer_entity', 'e', 'e.entity_id = n.nid');
$panelizer_nodes->fields('e', array('entity_id'));
$panelizer_nodes->condition('entity_type', 'node');
$panelizer_nodes->condition('did', 0, '<>');
$panelizer_nodes->condition('n.status ', 1, '=');
$panelizer_nodes->condition('n.type', 'content_type');

$result = $panelizer_nodes->groupBy('e.entity_id')->execute()->fetchCol('entity_id');
$nodes = node_load_multiple($result);

foreach ($nodes as $nid => $node) {
  // Set region based on layout.
  switch ($node->panelizer['page_manager']->display->layout) {
    case 'onecol_basic':
      $region = 'strip';
      break;
  }

  // Check if matching type.
  if ($region) {
    $panes = array();
    $my_block_pane_exists = FALSE;
    // Load the display.
    if ($display = panels_load_display($node->panelizer['page_manager']->display->did)) {
      // Get this display's panes.
      $panes = $display->content;
      // Reset the panes.
      $display->content = array();
      $display->panels[$region] = array();
      // Loop through and add in our new pane.
      foreach ($panes as $pid => $pane) {
        if ($pane->type == 'entity_field' && $pane->subtype == 'node:field_blog_author') {
          $my_block_pane_exists = TRUE;
        }
        // If my_block pane already exists we can skip this.
        // Set content.
        $display->panels[$region][] = $pid;
        $display->content[$pid] = $pane;
        // Add a new pane after the node_title pane.
        $new_pane = panels_new_pane('entity_field', 'node:field_blog_author', TRUE);
        $new_pane->panel = $region;
        $display->panels[$region][] = $new_pane->pid;
        $display->content[$new_pane->pid] = $new_pane;
      }
      // Finished reordering pane's, now save.
      if (!$my_block_pane_exists) {
        panels_save_display($display);
      }
    }
  }
}
?>