It is that unknown which has forced the 23-year-old to make the gut-wrenching decision to retire following a series of concussions.
He made the call after consultation with his family and Otago coach Rob Walter in the ''last month or so''.
With four serious concussions on his medical record, he came the conclusion it was not worth risking another.
Also, the brutal reality of professional sport hastened his decision. Teams had been targeting him with short-pitched bowling.
Hicks knew, if he was going to keep getting better, he would need to face plenty more bouncers and ultimately he was not prepared to keep putting himself in harm's way.
''I kind of got through that,'' Hicks said.
''But I didn't know a lot about the long-term effects of concussion.
''I started doing a bit of research and realised it was pretty serious.
''I thought I could work through it but then I had a lot of time to think.
''We went on holiday and spoke to family and I realised it was not just about me any more.
''I've got a wife, I'm going to have a family one day and it is my parents too. I don't want to put them in a position where they have to look after me.
''It is just the unknown which really got me. I could be fine but who knows, that last knock I had could be the one that pushed it over the line.
''I just don't know and I didn't see it as worth the risk.''
Hicks, who married Rozandrie (nee Lategan) in July last year, was a very promising rugby player. However, the South African-born talented second five-eighth suffered two heavy concussions while playing for Auckland Grammar School.
He picked up a third when fast bowler Scott Kuggeleijn struck him with a bouncer during a game between the New Zealand winter training squad and New Zealand A.
Then last year, Hicks was fielding in close when a shot from Wellington's Michael Bracewell clattered into his helmet.
It was a sickening blow. Hicks had been in tremendous form in all three formats but returned a changed player.
''When this season started I was struggling quite massively with just the thought of getting hit again.
''But also, in order for me to get better, I had to practise a lot against short balls and that does mean I'm going to get hit and I literally can't afford another hit.
''I had a lot of sleepless nights but the cons outweighed the pros.
''You've only got one head and you don't want to play around with it.''
Otago coach Rob Walter has supported Hicks while he wrestled with decision.
''Obviously, it is a big loss for the team but life trumps cricket,'' Walter said.
''I'm very respectful of the decision he has made. But we lose a tremendous guy ... who made an impact on and off the field.
''When batting to his potential he was devastating.
''We've seen him lap a ball for six and then hit it over long on and long off for six. He really was capable of doing great things with the bat.''
Hicks, who scored 651 first-class runs at an average of 23.25, will shift focus to his studies.
He has seven papers left to complete an accountancy degree.
