In Januray, the midfielder suffered a bad head injury after a clash with Chelsea's Garry Cahill.
Mason has already been treated by two doctors, however Hull's manager Slutsky said that he will visit a third specialist.
"It is a difficult situation on Mason, we have a difference of opinion and we are seeing a third doctor on Monday. It is not just about football but about his life. He wants to play but it is not an easy situation. It is more than football", the Russian said.
The former Spurs midfielder is fighting for his career and hopefully for him, the third specialist will help him to find a way to return to professional football.