But the effort required to complete a full game was too much for the injury which has caused him problems over the last two months.
An emotional Kennedy informed the manager on Wednesday morning that he would not be fit to travel when the squad leaves for Japan on Friday.
Reid was obviously overjoyed at his last-minute call-up to the Orient.
"I had booked a holiday a couple of days ago to Barbados," he told Millwall's official website.
''My brother had picked me up on Wednesday morning to take us to the airport.
''I turned my mobile on and there was a message from Mick McCarthy to ring him and he said that I'm going to Japan.
"To be in the Irish squad is a massive bonus and to play a second or a minute in the World Cup would be a dream come true."