The highly-rated 19-year-old has been on the books at the Emirates since January 2022, when he left West Bromwich Albion's youth academy to advance his career with the Gunners.
Sousa has made an impression for the Arsenal academy squads, coming up with five goals and one assist in 36 matches for the Under-21s, and he played a key role in the Gunners' run to the FA Youth Cup final last season.
The teenager has trained with Mikel Arteta's first team during his time in North London, but he has only made one Premier League matchday squad against Brentford in September 2022, when he was an unused substitute.
Sousa was most recently on the bench for Arsenal's 2-0 FA Cup loss to Liverpool earlier this month, prior to which there was hope that he would be handed his first-team debut in a Champions League dead rubber with PSV Eindhoven.
However, Sousa was left out of the squad for that 1-1 draw, where fellow academy graduates Ethan Nwaneri and Reuell Walters also both failed to make it onto the pitch, much to the disappointment of supporters.
Even with Oleksandr Zinchenko and Jurrien Timber struggling with injuries and Takehiro Tomiyasu competing at the Asian Cup, Sousa has not been given a look-in by Arteta, who has preferred centre-back Jakub Kiwior on the left flank in an emergency.
Now, journalist Fabrizio Romano reports that Sousa is on the verge of ending his two-year Arsenal spell to join Unai Emery's Aston Villa, who have beaten several other high-profile clubs to his signature.
Juventus, Rangers and Galatasaray were all said to have shown an interest in signing the ex-West Brom youngster, but Villa and Arsenal have now shaken hands on a permanent transfer.
Sousa is believed to have already completed his Villa medical, but rather than integrate him into the first team straight away, the Lions are reportedly planning to send him on loan to the Championship.
Romano adds that Plymouth Argyle have held discussions over acquiring Sousa's services for the remainder of the season, but Villa are yet to give the green light to the left-back heading to Home Park.
Should the deal go through without any late hold-ups, Sousa will become Arsenal's first permanent exit of the January transfer window, and he could potentially be one of two full-backs to wave goodbye to the Gunners for good.
Out-of-favour right-back Cedric Soares - whose contract runs out in the summer - is understood to be on the radar of Galatasaray, and teams in Turkey have until February 9 to conclude their transfer business.