Christian Oxlade-Chamberlain will leave Pompey to sign for Notts County.
The midfielder becomes a Magpies player when his Fratton Park contract expires at the end of this month.
Blues boss Kenny Jackett said: “We wish Christian all the best and he’s just about rehabilitated from the injury he suffered towards the end of last season.
"Hopefully he can build on the two years he had here as a professional and have a successful time at Notts County."
“Hopefully he can build on the two years he had here as a professional and have a successful time at Notts County.”
Oxlade-Chamberlain is a graduate of Pompey’s academy, who turned professional in the summer of 2016.
He made one senior appearance in an EFL Trophy defeat at Exeter and has had several spells out on loan, including at Oxford City last season.