Following Manchester United defender Jonny Evans' withdrawal through injury, Worthington attempted to add the highly-rated 20-year-old to his squad for the Euro 2012 qualifiers against Estonia on Friday and Italy on Tuesday but, not for the first time, he has found the left-back difficult to get hold of.
The question of allegiance was apparently put to bed when Ferguson accepted a call to play for Steve Beaglehole's Under-21 side again last month, but the latest non-appearance has clearly frustrated Worthington.
"I've been trying for the last 36-48 hours to get in contact with the boy to let him know I'd like to draft him into the squad," said the manager.
"His club has been notified and we've had the medical records sent back to us, as we always do with players to see if there are any problems, but we've had no contact.
"It beggars belief when you read in the press that people want to represent their country and when you give them the opportunity to do so there's no willingness, or manners, to say 'no I don't want to be involved' or 'Yes, I'm coming'.
"I can only do what I've done. People at the Irish Football Association have done what they do and we can't do any more.
"We can't put hands on and literally drag people in."