A WICB insider said Millien left the job "but was not really frustrated ... he just decided it was time to move on". The source was not willing to expand on the matter.
Millien, a Trinidadian, was instrumental in formulating several new marketing programmes, and played a key role in securing the multi-million-dollar Digicel sponsorship deal.
His departure is one of many this year from WICB office's in Antigua. WICB's chief executive officer Roger Brathwaite quit at the end of April after three years on the job. In January, Michael Seepersaud, the board's chief cricket development officer was fired, but WICB has not yet made this public.
Since these departures, Barry Thomas, the chief financial officer, has been acting chief executive officer and efforts to reach him on this and other matters have been unsuccessful. Seepersaud has also not been available for comment. West Indies team manager Tony Howard has been filling the role as chief cricket development officer.
Yesterday, former WICB president Pat Rousseau lambasted the board for failing to replace Brathwaite and other officers. He said it had taken "much too long. I would definitely say that".
"You can't run an office without a chief executive officer. That's impossible. That post should have been filled already. I don't know how they are doing it, but they need to move very quickly to fill it or the thing is going to get weaker and weaker. You can't run the board like that," the Jamaican told the Caribbean Media Corporation.
The WICB is holding two meetings in Barbados on Thursday. The first is to conclude the adjourned seventh annual meeting of members, which starts at 9 a.m.
Immediately afterward, they will move to a special meeting of directors at which they are seeking to appoint at least three non-member directors. If those appointments are effected, they would be unprecedented.