The keeper’s been training with the Blues and Kenny Jackett revealed he looks set to sign third-year scholarship terms.
Seymour will become the second triallist to win a deal, after fellow-stopper Duncan Turnbull penned terms in March.
But before that, there were no less than 15 players who Pompey run the rule over but didn't offer permanent deals. We've looked at where they all are today...
5. Ceykan Karagozlu
The winger featured for the reserves in October 2017 but was now let go. His Linkedin account says he’s the managing director of firm Marble Fantasy. | Colin Farmery Photo: Colin Farmery
6. Victor Adeboyejo
The striker had a brief spell with the Blues midway through the 2017-18 season. He’d subsequently joined Barnsley and had loan spells with Bristol Rovers and Cambridge this season. | EMPICS Sport Photo: John Walton
7. Bruno Andrade
Perhaps the one that got away? Andrade’s made a sound Football League career for himself after leaving Boreham Wood, helping Lincoln to League Two promotion before joining money-spinning Salford in January. | PA Archive/PA Images Photo: Paul Harding
8. Adam Henley
Featured for the reserves at Leicester in November 2018, featuring for a full 90 minutes at right-back. He’d join Real Salt Lake in the MLS but moved back to England last summer when signing for Bradford. Featured 27 times this term. | PA Archive/PA Images Photo: Dave Howarth