The game will now take place at 12.30pm ‘as a mark of respect’ to avoid clashing with the funeral of Prince Philip.
The Duke of Edinburgh died at the age of 99 on Friday.
His funeral will be held at St George's Chapel in Windsor at 3pm on Saturday, with a national minute's silence beginning at the same time.
The Blues’ game at the Dons had already been moved to 1pm.
However, it has been brought forward once more by half an hour as all sporting bodies in the UK adjust their schedules.
A total of 32 games across the Championship, League One and League Two had been due to kick-off at their traditional time of 3pm.
But these will either be rearranged as 12.30pm kick-offs or even played on Friday night.
Like Pompey, Charlton and Ipswich have already agreed for their league game at The Valley to begin at 12.30pm on Saturday.
Meanwhile, Northampton’s home game against Peterborough in League One will kick off at 7pm on Friday.
More confirmations are expected in due course.
A statement from the EFL read: ‘As a mark of respect, EFL matches scheduled for 3pm on Saturday 17 April, will be moved to avoid a clash with the funeral of HRH The Prince Philip, Duke of Edinburgh.
‘The EFL will now work with its clubs to determine at what time the matches will be played, giving consideration to the timing of the service.’