Gibson informed Republic of Ireland manager Giovanni Trapattoni that he was not in the right frame of mind to play for his country after the Republic of Ireland's poor Euro 2012 showing, but O'Shea has backed the Everton midfielder to return "sooner rather than later".
O'Shea told reporters: "I'm sure he will be back sooner rather than later.
"I have not spoken to him but I spoke to the manager about it and they have had a chat and they have come up with this decision.
"Darron felt he was not right at the minute to come in, but fingers crossed when he is ready he will be because he would be a good addition to the team."
Republic of Ireland begin their World Cup qualifying campaign against Kazakhstan on Friday.