Wide man Dobbin, 23, had a productive campaign on loan at Preston North End last season, scoring 11 goals and assisting a further eight.
Two of those goals came against Saints last season in PNE's 2-1 win at St Mary's in November, and their 3-1 defeat at Deepdale in May.
Dobbin came through the Everton academy and made 20 senior appearances, alongside a loan spell at Derby County during the 2022/23 League One season.
A permanent move to Villa followed in 2024 but he is yet to make a competitive appearance for the Villans, instead enjoying loan spells at West Brom, Norwich and Preston.
According to the Lancashire Evening Post, Saints are in the race to sign him alongside the likes of Middlesbrough and Wolves, while Sheffield United also reportedly hold a long-term interest.
Preston, who finished 14th in the second tier last season, have seemingly been priced out of bring back £10million-rated Dobbin on a permanent basis.
Saints have already made three permanent signings this summer, bringing back goalkeepers Daniel Peretz and George Long, as well as striker Cyle Larin following their loan spells at St Mary's in the second half of last season.
Bringing in a new forward is understood to be one of the club's priorities in this transfer window after failing to agree fresh terms with striker Ross Stewart.