Mario Lemina
Saints pulled off quite a coup to bring Lemina in from Juventus in 2017 and shelled out £15m to do so.
He was moved out on loan by Ralph Hasenhuttl though and reportedly told that he had no future at the club.
The Gabon international midfielder has impressed with Galatasaray this season and has played 23 times during his season-long loan.
Given that the Turkish side seem keen to bring him in permanently – and have an option to buy according to transfermarkt – Saints will be hopeful of recouping most of his original fee.