Red Shirt Rules?

I don't have good news.

What we refer to as a "medical redshirt" is called a hardship waiver by the NCAA.  

These waivers may be requested by the school (not the player) if a player sustains a documented season-ending injury before the team plays 20% of its scheduled games. Since your son returned to action, it wasn't a season-ending injury.  

Bludevil

First of all, I am going to be a little bit of an A$$ here.  Its not really up to you to contact the AD and figure this out.  Your son is now an adult and he needs to work through this with the school.  I currently have a son who is a frosh (non sport playing) and I know its hard to let him deal with things like this but in the end he will be better off for it.  I also know that when I was playing a sport in college (track) there was no way the coach or AD was going to have a discussion like this with a parent without having the student kick off the discussion and being present during it.

All the above said, most likely its too late to take the redshirt for the season.  It appears that he has played more then 20% of the season and his injury is not season ending.  The school would need to apply to the NCAA for the medical red shirt and it does not sound like he would meet the criteria.  About the only way I can think of to extend his time into his grad school year would be to take a redshirt later in his career.  You do not need to redshirt your frosh year.  He can take a redshirt at anytime.  This would extend out his tenure with the team to a 5th year but he would not be playing during the redshirt year.  He can practice buy not play.  The decision to redshirt him is up to the coach.  If the coach does not want to redshirt him he does not have to.  Also, be aware that if he is redshirted he takes the chance that a player will show up in his position and "take it away" from him.  

Swampboy, thank so much for the thoughtful reply. My discussion with the AD went well, he explained the fact that my son returned to play would not make the case black and white with the NCAA.

Kind regards and thank you.

Glad the AD could give you more encouragement than I could!

Looks like your son has done very well with his limited chances.  

Hope it works out for him.

Please keep us posted.