Danny Cowley is keen to explore a loan opportunity for the Championship right-back before the close of the transfer window on Tuesday night.
Romeo has been earmarked as a potential replacement for Callum Johnson at the back, following his loan departure for Fleetwood Town yesterday.
Interestingly, Cowley is in the market for a right-sided centre-back who can play centre-back.
That is proving tougher than anticipated, however, with Romeo primarily a right-back, although he did fill in centrally in a back three for Millwall last season.
The Londoner has picked up a stack of Championship experience after signing for the Lions from Gillingham in 2015, making 221 outings in all competitions.
Pompey are closing in on a deal for Miguel Azeez with Cowley is also in the market for a striker.
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