Are there no exceptions for that? I'm not a football fan so I don't know. Is that sort of like in baseball where you never ever see a pitcher with a single digit number on the back?

I have seen wide receivers wearing number 10. I think there is a guideline to go by, but certainly exceptions can , have, and will happen time to time.

@wonder2wonder said:

Steve's jersey number is not 50, but five-oh: "It's what my dad used to call our family, because we weren't native Hawaiian, so he nicknamed us five-oh's, after the 50th state in the Union"

In the NFL's current numbering system quarterbacks can have numbers 1-19. There are exceptions, so was there one made for Steve?

I don't think parents an select the number of their kids uniform. I think this was just written in for the show.