O'Neill admits that it will be next season before Campbell is back to his best after so long on the sidelines.
"To be involved in the Olympics would be pretty special," said O'Neill. "Fraizer came back in January and did brilliantly but, after so long out, it was always going to be next season before he was really back firing on all cylinders for us.
"When a player has been out for 15 months or so, it does take time until he gets back to where he was before and you have to remember that.
"However, if he is in the Olympic squad and gets the chance to play, that can only help him build towards next season."