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...
9. Jonathan Douglas.
Appeared for the reserves in a Premier League Cup clash against Leicester City at Nyewood Lane in February 2018. The former Ipswich and Leeds midfielder has since retired. | freelance Photo: Colin Farmery
10. Paul Paton
With Pompey short of centre midfielders, the Northern Ireland international spent a brief period at PO4 in March 2018 before joining Plymouth on a short-term deal. The 33-year-old is now representing Dunfermline Athletic. | PA Wire/PA Images Photo: Jeff Holmes
11. Ruben Sammut
Trained with Pompey towards the end of the 2017-18 campaign. The Chelsea midfielder impressed Kenny Jackett – but didn’t try to make a swoop. He’s now at Sunderland, although hasn’t featured once this season. | PA Archive/PA Images Photo: John Walton
12. Dimitar Evtimov
The keeper had a brief period with the Blues in January while Luke McGee was out injured. However, the former Burton Albion man left for Accrington where he’s made 21 outings this season. | 2019 Getty Images Photo: Nathan Stirk