Dion Donohue has thanked Pompey for stepping aside to allow him to seek regular first-team football.
The Blues possessed a club option on the versatile performer’s two-year contract, which expires next month.
Although deemed surplus to requirements, that clause would have extended the Welshman’s stay by 12 months, thereby handing Pompey the opportunity to demand a transfer fee.
The cultured left-footer became a father for the second time on Thursday, following the birth of daughter Maya.
And, after a frustrating season disrupted by illness and injury, he is grateful for Pompey’s gesture.
He said: ‘Everyone knows the club have an option, so they were well within their rights to take it up.
‘From a business point of view, they could easily have tried to get money and done a lot of things to hamper me, but showed me respect.
‘I’m grateful there was no malice and everyone was happy with the way it was handled.
‘Obviously I’m sad to be leaving, especially following the year I’ve had. I would have liked to have played a lot more and, if that was possible, I would have stayed.
‘I have always felt happy here, both my children were born here, but with the year I’ve had I need to go and play – and it was best for both parties. They did me a favour.
‘Considering the way this year has gone and how well the team have done, they will strengthen again in the summer, I'm sure.
‘For me to expect to go straight into the team is highly unrealistic and wouldn’t be fair on the lads who had done so well this season.
‘In the end, football-wise, it’s for the best, but I’m still sad to be leaving.’
Donohue arrived in August 2017 for an undisclosed fee from Chesterfield.
However, after contracting glandular fever in the summer, he endured an injury-ravaged second season, limiting him to just 13 games this term.
He added: ‘I’ve had a couple of conversions about where I’ll move to, but there's nothing concrete, I just have to wait and see.
‘In an ideal world, I would like to go closer to home, back up north, closer to the family now we’ve got two kids. Obviously beggars can’t be choosers.
‘A part of me is sad to be leaving, but on the flip side I have no regrets and am happy I played for Portsmouth.
‘It’s something I will always, always be proud of.’