It was a lack of respect for Dean by President-elect Barack Obama's team, they told Politico.
Obama named Virginia Gov. Tim Kaine as the new DNC chairman Thursday and recognized the work Dean has done during the last two election cycles to boost Democratic wins on a national and state level.
However, since the Nov. 4 election, Dean has been fairly quiet and apparently isn't being considered for a post within Obama's administration, the Washington publication said.
When Obama named Keane, Dean was in American Samoa doing DNC work,
"If he had been asked to go to that event, he would have been there," Jim Dean, the chairman's brother, told Politico.
"The snub (Thursday) was no accident," one Dean ally said. "I guarantee you he would have rescheduled his trip if asked to attend."
Asked about Dean's absence, Obama spokesman Ben LaBolt noted that the chairman was out of town and noted that Obama had praised Dean for his accomplishments.