The forward has scored eight goals under his new manager and it is little wonder that Mick McCarthy is making overtures to persuade the player, who has an Irish mother, to represent the Republic of Ireland.
Hasenhuttl said: "It is Reddy's decision who he feels he has to play for.
"He is having a fantastic development. He can make the difference. It is unbelievable that he was very much criticised last season in this stadium."