The 20-year-old measures in at a whopping 6 foot 4 and has already registered an impressive 20 appearances for the Saints, including 18 outings in the Premier League.
He failed to find the net in the Championship whilst on loan with MK Dons last season but bagged a maiden Premier League strike against Arsenal back in summer 2014.
The Sun, via The72.co.uk, reported last week that Blackburn Rovers were chasing a loan deal for the prodigious front-man and Ewood Park boss Owen Coyle has recently expressed his admiration for Gallagher.
The Daily Mail claim the Championship side are now on the verge of completing a deal for the former England U19, although they fail to confirm whether his transfer to Lancashire will be temporary or permanent.
Owen Coyle replaced Paul Lambert as Blackburn manager in July.