The News understands that the Bromley youngster visited the Blues' Hilsea training ground for discussions earlier this month.
As previously reported, Pompey have been casting their eyer over Vincent, having impressed for the Ravens this season.
The left-back has made seven appearances for the Hayes Lane outfit during their National League play-off push.
Vincent has come through the youth ranks at the Londonders and signed first-team terms in September before being handed his senior bow in February.
In addition, the 18-year-old has already displayed the Blues his prowess this season.
He starred for Bromley in their surprise 2-1 victory over Pompey Academy in the FA Youth Cup at Fratton Park in December.
Vincent scored the away side’s equalising goal before swinging in the corner that led to the Ravens’ match-winner.
As reported, Pompey head coach Danny Cowley will look to plunder the non-league market to find the young talent he feels his squad lacks.
There will likely be a few additions of that ilk in the coming months to supplement the large number of senior players Cowley is looking to bring in as part of his overhaul.
Should Vincent arrive, he’ll be one very much regarded as one for the future.
The Blues are looking to sign another senior left-back this summer ahead of a renewed League One promotion push next season.
With Charlie Daniels released at the end of his deal, Lee Brown is currently Pompey’s only left-sided full-back and an additional option is required.