The Blues had already declared their own business over following Thursday’s capture of Tino Anjorin on a season-long loan from Chelsea.
However, they were hopeful of finally offloading out-of-favour Hume on deadline day amid previous interest from Port Vale and Swindon.
Any prospective deal didn’t emerge, though, as the window ticked down without a breakthrough over the left-back.
It means Hume stays at Fratton Park with barely any likelihood of first-team appearances until January’s window opens.
The former Sunderland man himself was keen for a move to restart a career which has stalled significantly, yet, despite being available since May, he stays.
A setback for the Blues, nonetheless they remain happy with summer transfer window dealings which totalled 14 new arrivals to the south coast.
The likes of Regan Poole, Kusini Yengi, Christian Saydee and Will Norris have already made encouraging early impacts during the opening month of the campaign.
As for Hume, he hasn’t been involved in match action since named as an unused substitute against the Hawks in July.
Despite that ongoing absence, the former £200,000 man has continued to train with John Mousinho’s first-team squad.