The Hoops first-choice goalie Scott Bain could miss up to two months of action after sustaining a hand injury against Cluj during midweek’s Champions League qualifier.
While Craig Gordon is expected to start against the Cup clash against Dunfermline tomorrow, manager Neil Lennon wants to bring in another experienced goalie, and Forster could be keen to return to Celtic.
The 31-year-old is currently behind Angus Gunn and Alex McCarthy in the pecking order at Saint Mary Stadium.
The England international, who emerged as the Premier League Player of the Month in February 2016, helped Celtic to three titles and two cups, keeping most clean sheets in 2010–11, 2011–12, 2012–13 and 2013–14 while playing over 100 games under Lennon.
Forster joined Southampton five years ago for £10million and has since played six times for England.
Celtic are looking to win their ninth Scottish Premiership title on the row, and a quality goalkeeper like the Saints star can help them in Bain’s absence.
He knows the league in and out and will be a good addition to a dressing room that could do with more leaders and experience at the moment.