From the moment a player enters school, his "clock" starts ticking.  You
have 5 years to play 4 years of hockey.  If you will be 20 or older when
entering school, you lose one year of eligibility for each year you played
organized hockey somewhere else (i.e. Can jrs, Europe, etc.).  So some
players will enter college as a sophomore/junior eligibility-wise.
 
If a student transfers within the same division or up a division, he must
sit out for one school year from when he entered the new school.  So, if
you take a semester off and then enter a new school, you must wait in effect
almost a year and a half.  And so on.
 
Students transferring down a division are eligible immediately.  (Though
probably not, I believe, in cases when a player tries to enter the school
in the middle of the school year - you must be in school and have the
school accept you as a student.)
 
I'm not entirely sure on the rules regarding transfers practicing with the
team, etc.  I believe that because they are not eligible, they cannot take
part in any team activities, so they would have to practice separately until
becoming eligible.  This can be a problem for players slated to become
eligible in the middle of the year.  Especially goalies!  Rich Burchill,
who went to Northeastern from UNH, had to do this for a year (practice by
himself).  He still had an outstanding senior season.  (A plug for Burch -
one of the outstanding *people* I've known in the game.)
 
Red shirts are different from transfers.  Red shirts (players who enter but
don't play their first year, usually) can practice because they are eligible
and have 5 yrs to play 4.  They're just not playing their first year.
 
The NC$$ hockey rules and interpretations book does not have this information
in it, only playing rules, so be forewarned if you plan to order the book
and get this information.  I believe it would exist in the DivI operating
manuals.
 
Remember that players can file appeals with the NC$$ to have some of their
eligibility restored in certain extraordinary circumstances, such as
sustaining a season-ending injury very early in the year.  So these rules
are not steadfast.  They are usually pretty good on appeals.
 
 
- mike