The 20-year-old has signed for League Two Crawley until the end of the season after a period training with the Reds.
The young stopper moves from Isthmian South East outfit Burgess Hill Town, whom he joined following his Blues release at the end of last season.
Seymour made just one senior appearance for the Blues during his season-long stay at Fratton Park.
The former triallist came on as a second-half substitute for fellow rookie Duncan Turnbull in Pompey’s Papa John’s Trophy defeat at the hands of Peterborough in January 2021, conceding twice in the 5-1 loss.
He has made 26 appearances for the Hillian this season, keeping eight clean sheets, and is in the travelling Crawley party for today’s game at Northampton.
Welcoming him to The People's Pension Stadium, Reds boss John Yems said: ‘I’m happy to welcome young Taylor to the squad, he is a promising young goalkeeper and has been training with us for some time.
‘He will be able to learn from the experienced Glenn Morris which will be great for his game. I wish him all the best here at Crawley.’
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