The BCB stated that McMillan will work with the Bangladesh side only for the Sri Lanka series although Akram Khan, the cricket operations chairman, had said recently that the board is looking for a permanent batting coach.
McMillan had served as New Zealand batting coach from 2014 to the 2019 World Cup before taking up an IPL role with Kings XI Punjab. McMillan had also worked with Canterbury in Middlesex in the past.
The BCB wanted McKenzie to fulfill the role for the Test series in Sri Lanka, even though he was predominantly Bangladesh's white-ball coach, but he pulled out, citing family reasons.
McKenzie was appointed as Bangladesh's batting consultant in July 2018 under Steve Rhodes, and was one of the few survivors in the coaching staff after Bangladesh's early exit from the 2019 World Cup. McKenzie became an effective instructor and has often been credited by many Bangladesh batsmen for their progress in ODIs and T20Is.
Bangladesh will play three Tests in Sri Lanka, the first of which begins from October 24. The squad is set to leave for Colombo a month earlier to complete the mandatory quarantine before training.