Jack Whatmough has been ruled out of Pompey’s trip to Burton trip through England under-19 duty.
The central defender earlier this week linked-up with the Three Lions ahead of their match in Germany on Monday evening.
With England’s flight to Dusseldorf scheduled for Sunday, it has rendered him unavailable to the Blues for their televised fixture on the same day.
Whatmough has missed Pompey’s last two matches against Newport County and Yeovil after sustaining an injury to his left ankle in the Capital One Cup defeat at Stoke.
But he has been back in training since Monday and has had the all-clear to represent his country.
The friendly in Germany represents John Peacock’s final match in charge before handing the reins over to former AFC Bournemouth boss Sean O’Driscoll.
O’Driscoll – who was once interviewed for the Pompey job under Convers Sports Initiatives – will officially take over for the European Championship first qualifying round games in Luxembourg next month.
Whatmough will return to the Blues on Tuesday ahead of their trip to Southend on Saturday, September 13.
In the meantime, Nigel Atangana remains a major doubt to face Burton on Sunday.
Joe Devera (cricked neck) and Nick Awford (sore shoulder) are also struggling to make the trip to the Pirelli Stadium.
However, Ben Chorley is in the frame having recovered from the dead leg which kept him out at Yeovil in midweek.