The 24-year-old joined Stoke City on deadline day last month.
When questioned by the Daily Echoif Gunn has a future at St. Mary's, Hasenhuttl replied: "I'm really happy when you see players playing well on loan, from our side.
"Then I want to give everybody a chance to come back, but therefore they need to show up and they need to show that they develop their game.
"Because we are also moving forwards with our game and with our team, it's not easy to come back to be honest. But never say never."